Re: [OSM-talk] Mapping everything as areas
On Sun, Nov 29, 2009 at 1:25 AM, Anthony o...@inbox.org wrote: The whole point of using an area is that it doesn't behave like a line, though. If all you have is a line with a width, use a line with a width tag. Is it? Perhaps I missed the start of the conversation. I had presumed the whole point was so that the highway was not *limited* by the properties of a line. Essentially, I'm imagining a line of highly variable width. Is there a use case for a truly arbitrary shape? I mean, apart from random areas like oddly shaped carparks, pedestrian areas etc - which I assume is not what we're talking about. Steve ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sun, Nov 29, 2009 at 9:29 AM, Steve Bennett stevag...@gmail.com wrote: On Sun, Nov 29, 2009 at 1:25 AM, Anthony o...@inbox.org wrote: The whole point of using an area is that it doesn't behave like a line, though. If all you have is a line with a width, use a line with a width tag. Is it? Perhaps I missed the start of the conversation. I had presumed the whole point was so that the highway was not *limited* by the properties of a line. Yes, I agree. I'm not sure how what you said disagrees with what I meant. Perhaps my phrasing was sloppy. Essentially, I'm imagining a line of highly variable width. Is there a use case for a truly arbitrary shape? I mean, apart from random areas like oddly shaped carparks, pedestrian areas etc - which I assume is not what we're talking about. Well, yeah. Depending on what you mean by highly variable, a lot of them. Intersections, cul-de-sacs (turning circles), and roadways with traffic islands would be three which I come across all the time. I have a feeling that doesn't answer your question, though. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
A thought occurred to me, that people are only planning to use areas because editors don't easily allow for widths to be entered graphically. I wonder how much work it would be if you could draw the way and then stretch it sideways to fill out the extact area you wanted covered and then the editor simply attaches the width of the way as a tag etc. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sun, 29 Nov 2009 19:03:46 +0200, John Smith deltafoxtrot...@gmail.com wrote: A thought occurred to me, that people are only planning to use areas because editors don't easily allow for widths to be entered graphically. I wonder how much work it would be if you could draw the way and then stretch it sideways to fill out the extact area you wanted covered and then the editor simply attaches the width of the way as a tag etc. With areas you can explicitly map how neighboring ways are connected to each other, this is useful for sidewalks, lanes etc. If we were to map the ways with only simple way with a width, a relation would be needed to tell that you can hop from one way to the other, which is pretty cumbersome. Also the width of a way can sometimes be so variable, that you would have to split it in hundreds of pieces, which makes handling it very hard. Teemu Koskinen ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sun, Nov 29, 2009 at 1:12 PM, Teemu Koskinen teemu.koski...@mbnet.fi wrote: With areas you can explicitly map how neighboring ways are connected to each other, this is useful for sidewalks, lanes etc. If we were to map the ways with only simple way with a width, a relation would be needed to tell that you can hop from one way to the other, which is pretty cumbersome. Without good editor support, mapping highways as areas is already quite cumbersome. I guess you could use the parallel way feature in potlatch, or whatever the equivalent is in JOSM. But then you still have a quite a few steps after that. And if you're mapping side-by-side areas, you're going to probably want to use a multipolygon/boundary relation anyway, in order to make that connection explicit and in order to save yourself from lots of unnecessary duplication. That said, you raise an interesting solution to mapping lanes. If you mapped each lane as a multipolygon/boundary relation, you could even add tags to the shared ways which detail what type of lane changes are allowed. Since you're using a relation anyway, you could add some tags which help to indicate direction. Instead of outer and inner you could tag the ways as left, right, and end. Then you have a direction with which to use oneway=yes. All of this would have to be hidden by the editors, of course. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Mon, Nov 30, 2009 at 5:27 AM, Anthony o...@inbox.org wrote: Without good editor support, mapping highways as areas is already quite cumbersome. It's not so bad, for areas with good aerial imagery (I wouldn't call tracing cumbersome). And yes, not everywhere has good aerial imagery, but then again not everyone will be mapping areas :) ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Mon, Nov 30, 2009 at 3:03 AM, John Smith deltafoxtrot...@gmail.com wrote: A thought occurred to me, that people are only planning to use areas because editors don't easily allow for widths to be entered graphically. To some extent, perhaps... but the real reason is because the inherent nature of these objects in 2D (well, lat/long) is as an area. I wonder how much work it would be if you could draw the way and then stretch it sideways to fill out the extact area you wanted covered and then the editor simply attaches the width of the way as a tag etc. Nice idea, BUT then you are limited to a series of rectangles. In some situations, I think that will be too restrictive for not much gain. Of course, both options can and should be available to mappers! ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sun, Nov 29, 2009 at 4:56 PM, Roy Wallace waldo000...@gmail.com wrote: On Mon, Nov 30, 2009 at 5:27 AM, Anthony o...@inbox.org wrote: Without good editor support, mapping highways as areas is already quite cumbersome. It's not so bad, for areas with good aerial imagery (I wouldn't call tracing cumbersome). And yes, not everywhere has good aerial imagery, but then again not everyone will be mapping areas :) What's good? I tried it at z19, and it looked terrible, until I figured out the parallel way trick. On Sun, Nov 29, 2009 at 5:00 PM, Roy Wallace waldo000...@gmail.com wrote: On Mon, Nov 30, 2009 at 3:03 AM, John Smith deltafoxtrot...@gmail.com wrote: I wonder how much work it would be if you could draw the way and then stretch it sideways to fill out the extact area you wanted covered and then the editor simply attaches the width of the way as a tag etc. Nice idea, BUT then you are limited to a series of rectangles. You can do curves that way. It's effectively the same algorithm as the parallel way in Potlatch, except you wouldn't have to connect the two ways together manually. The calculus of how we get two ways with different lengths to be parallel is eluding me, but whatever that algorithm is, that's the one that makes sense. I believe the answer is that technically, the lines aren't really parallel. Is there another term for it? Does anyone know what I mean? ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Mon, Nov 30, 2009 at 9:00 AM, Roy Wallace waldo000...@gmail.com wrote: Nice idea, BUT then you are limited to a series of rectangles. In some situations, I think that will be too restrictive for not much gain. A series of quadrilaterals, perhaps. If width=10, then 50 metres later, width =15, I'd expect a quadrilateral gradually getting wider from 10 to 15. Steve ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Mon, Nov 30, 2009 at 8:29 AM, Steve Bennett stevag...@gmail.com wrote: Nice idea, BUT then you are limited to a series of rectangles. In some situations, I think that will be too restrictive for not much gain. A series of quadrilaterals, perhaps. If width=10, then 50 metres later, width =15, I'd expect a quadrilateral gradually getting wider from 10 to 15. If you apply widths to the nodes, I guess, yeah, it would be possible for a renderer etc. to interpret these as requiring linear interpolation. But approximation with trapezoids or whatever is a bit fudgye.g. what if you *do* want to represent an instantaneous change in width? My point is that this general suggestion seems to be a way to *map areas*, by *tagging ways*. Is this actually better than to *map areas* by *tagging areas*? If so, how? ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Mon, Nov 30, 2009 at 10:09 AM, Roy Wallace waldo000...@gmail.com wrote: interpolation. But approximation with trapezoids or whatever is a bit fudgye.g. what if you *do* want to represent an instantaneous change in width? I can think of several options, and I'm sure you can too :) My point is that this general suggestion seems to be a way to *map areas*, by *tagging ways*. Is this actually better than to *map areas* by *tagging areas*? If so, how? I can think of a few reasons it would be better: * No parallel data structures. Ie, there is just a way, with markup, rather than a way and an area. (I don't think simplying have an area without a way is viable, as it imposes too great a burden on routing software.) * Conceptually cleaner. From the point of view of a map, a road really is a line...that happens to have some width and shape. Mapping it as an area makes it primarily a chunk of asphalt...that you happen to be able to drive along to get somewhere. The ideal situation would probably be to have users be able to enter either ways or areas, and have the server software understand the relationship between them, and convert between them. So if you enter a way, it automatically creates an implicit area around it with some default width. Nice client software might let you manually tweak that area. This aspect of GUIs is very hard to get right though: when there are automatic/implicit data structures that are occasionally customised. What happens if you customise the shape of the road, then re-route the way? There's never a very clean answer to that question. (Possibilities are, keep the area - even if it's out of sync; discard the area information; attempt to preserve some of the area information - even if it now makes no sense...) Steve ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Mon, Nov 30, 2009 at 10:23 AM, Steve Bennett stevag...@gmail.com wrote: On Mon, Nov 30, 2009 at 10:09 AM, Roy Wallace waldo000...@gmail.com wrote: interpolation. But approximation with trapezoids or whatever is a bit fudgye.g. what if you *do* want to represent an instantaneous change in width? I can think of several options, and I'm sure you can too :) Of course, but they're all a bit fudgy :P My point is that this general suggestion seems to be a way to *map areas*, by *tagging ways*. Is this actually better than to *map areas* by *tagging areas*? If so, how? I can think of a few reasons it would be better: * No parallel data structures. Ie, there is just a way, with markup, rather than a way and an area. (I don't think simplying have an area without a way is viable, as it imposes too great a burden on routing software.) Yup, valid point. * Conceptually cleaner. I'm not entirely sure what conceptually cleaner means. From the point of view of a map, a road really is a line...that happens to have some width and shape. Mapping it as an area makes it primarily a chunk of asphalt...that you happen to be able to drive along to get somewhere. Hmm...I think these are *both* valid interpretations of a road. I don't think it's a strong argument against mapping areas explicitly. The ideal situation would probably be to have users be able to enter either ways or areas, and have the server software understand the relationship between them, and convert between them. Agreed. The issue remains of whether the server should convert everything to 1) split ways with width tags, implying linear interpolation between segments with different widths or 2) a way and an area, possibly linked with a relation. I prefer the second, as it more clearly encapsulates the two aspects of a road that you have pointed out above: 1) a line you drive along and 2) a chunk of asphalt. So if you enter a way, it automatically creates an implicit area around it with some default width. A default width is not necessary. The absense of a width tag should imply the width is unknown/unspecified. Or, in other words, the default is the road is a *line* (0 width, no area). Nice client software might let you manually tweak that area. This aspect of GUIs is very hard to get right though: when there are automatic/implicit data structures that are occasionally customised. Should be less of a problem when area is only implied after additional user input. What happens if you customise the shape of the road, then re-route the way? There's never a very clean answer to that question. (Possibilities are, keep the area - even if it's out of sync; discard the area information; attempt to preserve some of the area information - even if it now makes no sense...) Not entirely sure what you mean, but in general, I would say give the mapper control (e.g. discard information only when requested). ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Nov 29, 2009, at 5:01 PM, Roy Wallace wrote: From the point of view of a map, a road really is a line...that happens to have some width and shape. Mapping it as an area makes it primarily a chunk of asphalt...that you happen to be able to drive along to get somewhere. Hmm...I think these are *both* valid interpretations of a road. I don't think it's a strong argument against mapping areas explicitly. I think it's a strong argument for scale-dependent mapping of areas vs. ways. Both are valid interpretations, but not on the same view of a map. I think having a variety of data sets would help here. The ideal situation would probably be to have users be able to enter either ways or areas, and have the server software understand the relationship between them, and convert between them. Agreed. The issue remains of whether the server should convert everything to 1) split ways with width tags, implying linear interpolation between segments with different widths or 2) a way and an area, possibly linked with a relation. I prefer the second, as it more clearly encapsulates the two aspects of a road that you have pointed out above: 1) a line you drive along and 2) a chunk of asphalt. This muddles too many needs into a single data set, and the idea of the server converting things could introduce a lot of problems. I agree that the road can be two things, but I don't think it can be those two things at once. -mike. michal migurski- m...@stamen.com 415.558.1610 ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Using areas seems like a lot of work for no benefit if you just need a simple 2 lane road that has no foot paths or other interesting features. Are you saying that you wouldn't find mapping areas satisfying? If so, that's fine - you don't have to. But for people who want to do it, they should be able to. That's what this thread is about - giving them a way to map the world more accurately, if that's what they're into. There's nothing stopping anyone mapping highways as areas. However, it could be a long time until routers and renderers catch up; the majority of the world wouldn't be able to position the areas accurately enough to make this worthwhile; GPS errors approaching the size of some roads; no suitable aerial imagery; lack of time to get the theodolite out everywhere... For renderers: *nearly all maps exaggerate road width except when really zoomed in. A 30-35 metre wide motorway would appear almost insignificant at z levels less than 10 or 12 - but this is precisely the opposite of what we'd want; motorways should be significant roads when zoomed out. You'd have to find a way of expanding the areas to make these more significant. For routers: *routing over areas is much harder than routing along ways between nodes. Directions are not defined so one-ways are meaningless. You could do routing over areas, with some pre-processing, but it would 'break' a number of existing established routers In summary, I have no problem with people mapping everything as areas; however, I believe for the moment we will have to use both areas and ways. Most wide rivers mapped as areas I've seen also have a way down the centreline - to define the river name, and direction of flow. More importantly, using both ways and areas would render the way we'd expect; wider when zoomed out because the way is rendering wider than the area; wider when zoomed in because we are seeing the visible extent of the area, and we can have street names rendered in the right direction down the centreline. For routers we can continue to follow the ways as navigation paths, ignoring areas, and we can define the direction of travel for one-way streets. Richard ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sat, Nov 28, 2009 at 10:08 PM, Richard Bullock rb...@cantab.net wrote: For renderers: * nearly all maps exaggerate road width except when really zoomed in. A 30-35 metre wide motorway would appear almost insignificant at z levels less than 10 or 12 - but this is precisely the opposite of what we'd want; motorways should be significant roads when zoomed out. You'd have to find a way of expanding the areas to make these more significant. Maybe I missed the crucial bit, but presumably any area=yes highway has an implicit line running down the middle of it. The renderer would use that line at lower zoom levels exactly as it uses any other line. This does all assume that the area really does behave like a line. If people get creative with T shapes or whatever, then it would break down. For routers: * routing over areas is much harder than routing along ways between nodes. Directions are not defined so one-ways are meaningless. You could do routing over areas, with some pre-processing, but it would 'break' a number of existing established routers I was thinking about this before, surely you can directionalise an area by defining a start *way* and an end *way* just as a line has a start node and end node. Again, assumes an area that is still kind of linear in shape. In summary, I have no problem with people mapping everything as areas; however, I believe for the moment we will have to use both areas and ways. Most wide rivers mapped as areas I've seen also have a way down the centreline - to define the river name, and direction of flow. More importantly, using both ways and areas would render the way we'd expect; wider when zoomed out because the way is rendering wider than the area; wider when zoomed in because we are seeing the visible extent of the area, and we can have street names rendered in the right direction down the Yep, it seems to work well in practice, too. A map that is all areas and no lines isn't really a map anymore, it's a floor plan or a diagram. Maps intentionally simplify the real world, to make it easier to understand. centreline. For routers we can continue to follow the ways as navigation paths, ignoring areas, and we can define the direction of travel for one-way streets. Surely a good router would find paths within areas that are not along its boundaries...? Steve ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sat, Nov 28, 2009 at 6:08 AM, Richard Bullock rb...@cantab.net wrote: In summary, I have no problem with people mapping everything as areas; however, I believe for the moment we will have to use both areas and ways. If you're going to use an area and a way, don't tag them both with highway=*. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sat, Nov 28, 2009 at 8:47 AM, Steve Bennett stevag...@gmail.com wrote: Maybe I missed the crucial bit, but presumably any area=yes highway has an implicit line running down the middle of it. The renderer would use that line at lower zoom levels exactly as it uses any other line. That kind of destroys the whole point of highway areas, which is that you are free to travel in any direction you want. If I were going to write a renderer for it, I'd take the N nodes which connect in and then make (N)(N-1) lines connecting them via the shortest path (lines as straight as possible such that they fit within the area, I'm sure there's a simple algorithm for it). That'd be run as a pre-processing step, at which point I'd throw away the areas. This does all assume that the area really does behave like a line. If people get creative with T shapes or whatever, then it would break down. The whole point of using an area is that it doesn't behave like a line, though. If all you have is a line with a width, use a line with a width tag. I was thinking about this before, surely you can directionalise an area by defining a start *way* and an end *way* just as a line has a start node and end node. Again, assumes an area that is still kind of linear in shape. In many cases this wouldn't even be necessary, because the connecting ways will be one-way. Even with a T-shape, if the ins and outs are one-way, so is the area by implication. In more complicated situations, turn restrictions could work. However, yes, once it's anything but a line with a width, you're not representing a typical street. And even if you do have a line with a width, if there's more than one lane you're not really capturing the true rules of the road, which include a requirement to generally stay in one lane. A two-lane area stretching for a kilometer would imply to routers that it's perfectly acceptable to drive in a diagonal line from one lane to another - generally not something that's allowed. If you want to go in the direction of mapping the purely physical, then for a multi-lane roadway you'd want to map the area and the lane separators. Then the routers would have a lot of pre-processing work ahead of them, where they'd probably take all those areas and convert them (back) into lines and nodes. On the other hand, renderers would have a piece of cake. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 8:11 AM, Jean-Marc Liotier j...@liotier.org wrote: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Ævar's example is interesting. Looks like somebody is doing some area- / micro- mapping in OSM as well. Open this in an editor to see all of the detail work. http://bestofosm.org/?type=mapniklon=11.42994lat=51.30053zoom=18 Some will look at this and say, Too much! Impractical! We must map City $n first. Others will say, Where is the detail? I don't see catch-basins. Where are the expansion joints in the sidewalk? No height tag for the curb; what shoddy work! That mapper hasn't drawn areas for the painted lines on the road! Each of us will have a different perspective on how much detail is enough or too much. Why not show us your examples as Ævar and Mirko Küster have. I think that there are a number of interesting challenges ahead for area- / micro- mapping. And probably some breathtaking renderings. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On 25/11/09 21:59, Roy Wallace wrote: This raises another interesting question, that is, whether highways=* should *necessarily* express logical paths of travel, or whether they are just a convenient way to represent an *area* used as a path of travel, as a placeholder for future, more detailed mapping (e.g. as an area). Even the logical viewpoint benefits from roads as areas. When they are areas, they have two sides, and things (house numbers, postboxes, bus stops) can profitably be unambiguously attached to the appropriate edge. When they are lines, the bus stop has to be an extra node placed an arbitrary distance to the side, and is not connected to the road unless you go to the trouble of defining a relation. Gerv ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
I've been seeing this thread develop, and apart from trying to use areas and relations in all sorts of weird and wonderful ways wouldn't it be simpler from a logical point of view to treat ways as a grouping of lanes and those lanes can be assigned tags that differ from the ways, such as directions. Using areas seems like a lot of work for no benefit if you just need a simple 2 lane road that has no foot paths or other interesting features. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sat, Nov 28, 2009 at 5:47 AM, John Smith deltafoxtrot...@gmail.com wrote: I've been seeing this thread develop, and apart from trying to use areas and relations in all sorts of weird and wonderful ways wouldn't it be simpler from a logical point of view to treat ways as a grouping of lanes and those lanes can be assigned tags that differ from the ways, such as directions. Is a lane a directed area? If it isn't an area, then it's not really relevant to this thread, is it? Using areas seems like a lot of work for no benefit if you just need a simple 2 lane road that has no foot paths or other interesting features. Are you saying that you wouldn't find mapping areas satisfying? If so, that's fine - you don't have to. But for people who want to do it, they should be able to. That's what this thread is about - giving them a way to map the world more accurately, if that's what they're into. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Fri, Nov 27, 2009 at 2:47 PM, John Smith deltafoxtrot...@gmail.com wrote: Using areas seems like a lot of work for no benefit if you just need a simple 2 lane road that has no foot paths or other interesting features. Yeah, that would be a bad place to use an area :). Areas would be beneficial for, well, just about everything else :). ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Fri, Nov 27, 2009 at 3:37 PM, Roy Wallace waldo000...@gmail.com wrote: But for people who want to do it [map areas], they should be able to. That's what this thread is about - giving them a way to map the world more accurately, if that's what they're into. Right now, what's stopping them? ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sat, Nov 28, 2009 at 6:47 AM, Anthony o...@inbox.org wrote: On Fri, Nov 27, 2009 at 3:37 PM, Roy Wallace waldo000...@gmail.com wrote: But for people who want to do it [map areas], they should be able to. That's what this thread is about - giving them a way to map the world more accurately, if that's what they're into. Right now, what's stopping them? Documentation. Or, in other words, at least some suggestions as to how to do it. For example, you'll notice that Map Features states that highway's are ways, not areas. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Fri, Nov 27, 2009 at 3:49 PM, Roy Wallace waldo000...@gmail.com wrote: On Sat, Nov 28, 2009 at 6:47 AM, Anthony o...@inbox.org wrote: On Fri, Nov 27, 2009 at 3:37 PM, Roy Wallace waldo000...@gmail.com wrote: But for people who want to do it [map areas], they should be able to. That's what this thread is about - giving them a way to map the world more accurately, if that's what they're into. Right now, what's stopping them? Documentation. Or, in other words, at least some suggestions as to how to do it. For example, you'll notice that Map Features states that highway's are ways, not areas. Weird. http://wiki.openstreetmap.org/wiki/Tag:area%3Dyes says that highways can be areas. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sat, Nov 28, 2009 at 6:51 AM, Anthony o...@inbox.org wrote: Right now, what's stopping them? Documentation. Or, in other words, at least some suggestions as to how to do it. For example, you'll notice that Map Features states that highway's are ways, not areas. Weird. http://wiki.openstreetmap.org/wiki/Tag:area%3Dyes says that highways can be areas. Interesting, thanks for that link - it appears to be easy to overlook - for me, anyway. Note, though, that the Key:area page states area=yes, in the context of roads, indicates that the area has no street lines within it. I expect we will want this restriction lifted at some point, to be able to indicate the area occupied by long roads, or roads with a direction. I guess the questions remain: 1) how to indicate an area's direction 2) whether it is necessary/most convenient (in some situations) to represent a particular highway as both a way AND an area 3) if so, how to relate a physical area to the corresponding logical way, if that's even necessary/recommended Apologies if this has been discussed before - if it has, please point me to the relevant discussion page :) ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
2009/11/28 Roy Wallace waldo000...@gmail.com: On Sat, Nov 28, 2009 at 5:47 AM, John Smith deltafoxtrot...@gmail.com wrote: I've been seeing this thread develop, and apart from trying to use areas and relations in all sorts of weird and wonderful ways wouldn't it be simpler from a logical point of view to treat ways as a grouping of lanes and those lanes can be assigned tags that differ from the ways, such as directions. Is a lane a directed area? If it isn't an area, then it's not really relevant to this thread, is it? That depends if you are you only after opinions that agree with yours, or if you really want a solution to a problem. Are you saying that you wouldn't find mapping areas satisfying? If so, that's fine - you don't have to. The map data is already inconsistent for a variety of reasons, why make it even more so, I was pointing out a solution that builds upon the existing logic and can cascade rather than be forced to do a lot of extra work for no extra benefit. But for people who want to do it, they should be able to. That's what this thread is about - giving them a way to map the world more accurately, if that's what they're into. Sure you can go map sewers if you want, but you are describing a radical change that is in conflict with vast amounts of existing map data. My suggestion was to build on the existing data and cascade down to further describe it at a smaller level. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Fri, Nov 27, 2009 at 4:09 PM, Roy Wallace waldo000...@gmail.com wrote: On Sat, Nov 28, 2009 at 6:51 AM, Anthony o...@inbox.org wrote: Right now, what's stopping them? Documentation. Or, in other words, at least some suggestions as to how to do it. For example, you'll notice that Map Features states that highway's are ways, not areas. Weird. http://wiki.openstreetmap.org/wiki/Tag:area%3Dyes says that highways can be areas. Interesting, thanks for that link - it appears to be easy to overlook - for me, anyway. Note, though, that the Key:area page states area=yes, in the context of roads, indicates that the area has no street lines within it. I expect we will want this restriction lifted at some point, to be able to indicate the area occupied by long roads, or roads with a direction. I guess the questions remain: 1) how to indicate an area's direction Areas don't have a direction :). When you try to combine the physical with the logical, problems arise. 2) whether it is necessary/most convenient (in some situations) to represent a particular highway as both a way AND an area More likely a particular highway, like Dale Mabry Highway, would be represented by *many* ways and *many* areas. 3) if so, how to relate a physical area to the corresponding logical way, if that's even necessary/recommended Depends what you want to show. To show that a way travels over a particular paved section of road, the geometry should be adequate. On the other hand, to show that these paved areas, plus these sidewalks, plus these center-islands, plus these ways, etc., make up Dale Mabry Highway, sounds like a job for a relation. Apologies if this has been discussed before - if it has, please point me to the relevant discussion page :) It has been discussed ad-nauseum in some form or another as long as I've been reading this mailing list. But there haven't been many conclusions made :). ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Sat, Nov 28, 2009 at 7:32 AM, John Smith deltafoxtrot...@gmail.com wrote: Is a lane a directed area? If it isn't an area, then it's not really relevant to this thread, is it? That depends if you are you only after opinions that agree with yours, or if you really want a solution to a problem. Which problem are you talking about? For me, the problem is finding a way to map everything as areas. I don't see how your solution addresses that problem. Please explain how tagging lanes helps with mapping everything as areas (see the topic of this thread)... Are you saying that you wouldn't find mapping areas satisfying? If so, that's fine - you don't have to. The map data is already inconsistent for a variety of reasons, why make it even more so, I was pointing out a solution that builds upon the existing logic and can cascade rather than be forced to do a lot of extra work for no extra benefit. Sounds great, but thus far I don't see how it helps with mapping areas... But for people who want to do it, they should be able to. That's what this thread is about - giving them a way to map the world more accurately, if that's what they're into. Sure you can go map sewers if you want, but you are describing a radical change that is in conflict with vast amounts of existing map data. My suggestion was to build on the existing data and cascade down to further describe it at a smaller level. Again, sounds great. But please describe a way to map everything as areas - or perhaps it is worthwhile starting a new thread? ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On 25/11/2009, at 14.11, Jean-Marc Liotier wrote: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Talking about roads: I don't see the point mapping roads as areas. There's not much you do with an area that can't in principle be done using a line with appropriate tagging. The problem is that the current tagging namespace is too simple and not expressive enough to allow it. For example, if I write highway=residential cycleway=track width=3 there's no way for you to know if width=3 describes the cycleway or the road itself. In my view it would make much more sense to work on a more expressive (perhaps BNF based?) tagging scheme. This would enable a gradual enhancement of the map, where the new tagging syntax could live along-side the old. Areas are reminicent of the map-drawing approach to the map, in the sense that mankind has been drawing maps with paper and pencil for thousands of years. The map-drawing approach is valuable in OSM because it allows us to indicate residential areas parks, etc. However, in addition, OSM has a graph-based approach for a description of the network of roads which makes it *uniquely* valuable. Graphs prefectly represents the road map and can be used for many applications, routing is an example that many people use daily. Conversely, there isn't much you can do with graphs that can't be done with areas, and since the map-drawing approach has great appeal to people enjoying beautiful and detailed maps, the pressure for deprecating the graph-based approach in favour of the map-drawing approach will be ever increasing. We need to resist that. Let's not throw out the baby with the bath- water! Cheers, Morten ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Morten Kjeldgaard wrote: On 25/11/2009, at 14.11, Jean-Marc Liotier wrote: The map-drawing approach is valuable in OSM because it allows us to indicate residential areas parks, etc. However, in addition, OSM has a graph-based approach for a description of the network of roads which makes it *uniquely* valuable. Graphs prefectly represents the road map and can be used for many applications, routing is an example that many people use daily. Graph is the word I was looking for... Thanks for introducing it to the debate. Indeed the graph (nodes+edges) is the simplest way to model a network. In modeling, the simplest way is likely to be the best. But if we map everything as an area, do we lose the ability to perform graph calculations ? Can't an area be considered as a set of edges connecting all nodes inside it ? In my view it would make much more sense to work on a more expressive (perhaps BNF based?) tagging scheme. This would enable a gradual enhancement of the map, where the new tagging syntax could live along-side the old. From my OpenStreetMap novice point of view, modeling ordered sub-ways inside a highway, each with its own set of tags would go a long way toward removing the need to model ways as areas. Special cases would remain, but if for a given way I can define the order of sidewalk, bicycle lane, bus lane, car lanes, separators and whatever else, each with speed limit, width and various other tags, I barely see the need for area mapping of ways. Is there any problem with this approach ? It would introduce hierarchy and ordering, but it would reuse all the existing tags and remain compatible with the existing scheme. Notice that introducing hierarchy and ordering fits the existing OpenStreetMap XML schema quite naturally: all that would be needed is to nest a way inside a way - except that the nested way would have no nd but only tags. Conversely, there isn't much you can do with graphs that can't be done with areas, and since the map-drawing approach has great appeal to people enjoying beautiful and detailed maps, the pressure for deprecating the graph-based approach in favour of the map-drawing approach will be ever increasing. We need to resist that. Let's not throw out the baby with the bath- water! I now realize that there is a big risk of diluting the model. So maybe finding a way to make the model more expressive without changing its focus from graph to areas is a better way to address the need without losing what we have. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On 26/11/2009, at 09.47, Morten Kjeldgaard wrote: Conversely, there isn't much you can do with graphs that can't be done with areas, and since the map-drawing approach has great appeal to people enjoying beautiful and detailed maps, the pressure for deprecating the graph-based approach in favour of the map-drawing approach will be ever increasing. There is a construction that might bridge the gap between areas and graphs. In lack of a better word, I will call it a multiplex for now (I am sure there's a better word.) Imagine an area like seen in the attached file (ASCII art). It represents an area that could be an intersection. On the edges of this polygon some hot-spots labelled A-H have been defined. The shape of the polygon and the position of hot-spots on the edges is arbitrary and can be defined by the user. The nice thing about the multiplex is that lines (ways) can connect to the hot-spots from the outside, and the multiplex itself contains information about how the hotspots are connected internally. So for example, if the multiplex in the example represents an intersection, you would connect B-D (left turn from B), B-F (going straigh ahead from B), B - D (right turn from B). And so on, to make all other possible connections inside the intersection. This would give you an object which would render nicely as an intersection, and there's of course the option of tagging a bunch of auxilliary information such number of traffic_lights, directional signs etc. (This example is for right-lane traffic. In countries with left traffic, you'd do it differently) Cheers, Morten --C--D-- || || -- -- | | A E | | B F | | -- -- || || --G--H-- ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
2009/11/26 Morten Kjeldgaard m...@bioxray.dk: So for example, if the multiplex in the example represents an intersection, you would connect B-D (left turn from B), B-F (going straigh ahead from B), B - D (right turn from B). And so on, to make all other possible connections inside the intersection. This would give you an object which would render nicely as an intersection, and there's of course the option of tagging a bunch of auxilliary information such number of traffic_lights, directional signs etc. How would you measure the distance from, for example, B-D? It's not a straight line. A minor error, I suppose, for an intersection, especially a simple intersection like the one you've outlined, but if the concept is going to be extended beyond intersections, the error could potentially be expanded as well. And if we're going to take the time to carefully micromap an intersection as an area, we might as well be as accurate as possible. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Anthony wrote: 2009/11/26 Morten Kjeldgaard m...@bioxray.dk: So for example, if the multiplex in the example represents an intersection, you would connect B-D (left turn from B), B-F (going straigh ahead from B), B - D (right turn from B). And so on, to make all other possible connections inside the intersection. This would give you an object which would render nicely as an intersection, and there's of course the option of tagging a bunch of auxilliary information such number of traffic_lights, directional signs etc. How would you measure the distance from, for example, B-D? It's not a straight line. A minor error, I suppose, for an intersection, especially a simple intersection like the one you've outlined, but if the concept is going to be extended beyond intersections, the error could potentially be expanded as well. And if we're going to take the time to carefully micromap an intersection as an area, we might as well be as accurate as possible. Good question :-) It is indeed true that this concept could be expanded to deal with, say, a six-lane highway, a cloverleaf intersection, etc. Fascinating... Well, the internal connections would be constructed from nodes and ways inside the object (but encapsulated from the outside world, so they are only accessible from the object/multiplex itself.) Therefore, the object knows the length of it's internal connections and should be able to answer that question. (Perhaps it sounds like I'm talking about a C++ object but I hope you get the meaning.) In the meantime, I've elaborated a little bit on this idea, illustrated with somewhat more detailed pictures of the intersection. It's on my wiki page [0]. I made these before starting to think about your question, so the internal connections you see in one of the image are made up of just straight lines. It does, however, deal with the internal routing in the object. Like you said, it would give errors when attempting to measure distances, but in the case of an intersection those errors would be extremely small (the object would have to measure the distance from B to the node that branches off to D plus the distance from there to D, ignoring the fact that a car would take a shorter curve through the intersection.) Cheers, Morten [0] http://wiki.openstreetmap.org/wiki/User:Mok0#Multiplex_suggestion ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
2009/11/26 Anthony o...@inbox.org: 2009/11/26 Morten Kjeldgaard m...@bioxray.dk: How would you measure the distance from, for example, B-D? It's not a straight line. A minor error, I suppose, for an intersection, especially a simple intersection like the one you've outlined, but if the concept is going to be extended beyond intersections, the error could potentially be expanded as well. And if we're going to take the time to carefully micromap an intersection as an area, we might as well be as accurate as possible. You can calculate the shortest path from A to B that lies entirely within the polygon, but: 1. the vehicle is not (usually) a point, it has a width and length, the shortest path will be different for a lorry and a bike, 2. a car is not going to take the shortest path either, it has to align to: the traffic rules, how tight a turn it can make, etc. Most of the times it's going to be using the middle of some lane independent of the vehicle size so the way we have the centrelines on the map is really convenient. Cheers ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Morten, On Thu, Nov 26, 2009 at 10:18 AM, Morten Kjeldgaard m...@bioxray.dk wrote: It is indeed true that this concept could be expanded to deal with, say, a six-lane highway, a cloverleaf intersection, etc. Fascinating... Well, the internal connections would be constructed from nodes and ways inside the object (but encapsulated from the outside world, so they are only accessible from the object/multiplex itself.) Therefore, the object knows the length of it's internal connections and should be able to answer that question. (Perhaps it sounds like I'm talking about a C++ object but I hope you get the meaning.) In the meantime, I've elaborated a little bit on this idea, illustrated with somewhat more detailed pictures of the intersection. It's on my wiki page [0]. [snip] [0] http://wiki.openstreetmap.org/wiki/User:Mok0#Multiplex_suggestion I think it's great. The multiplex acts sort of like a relation, except that it enforces certain constraints rather than letting people build structures which don't make logical sense. I think the concept could be extremely extensible. What do you think about implementation? From a database standpoint, it looks like a type of relation. But who enforces the constraints? Server-side would certainly best protect the data from corruption. Editor imposed constraints would be more in tune with the current OSM philosophy (let the mappers do whatever the editors let them do, and just mark logically nonsensical situations in weblint). Any way you can think of that I might be able to help? Anthony ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Anthony wrote: Morten, On Thu, Nov 26, 2009 at 10:18 AM, Morten Kjeldgaard m...@bioxray.dk wrote: It is indeed true that this concept could be expanded to deal with, say, a six-lane highway, a cloverleaf intersection, etc. Fascinating... Well, the internal connections would be constructed from nodes and ways inside the object (but encapsulated from the outside world, so they are only accessible from the object/multiplex itself.) Therefore, the object knows the length of it's internal connections and should be able to answer that question. (Perhaps it sounds like I'm talking about a C++ object but I hope you get the meaning.) In the meantime, I've elaborated a little bit on this idea, illustrated with somewhat more detailed pictures of the intersection. It's on my wiki page [0]. [snip] [0] http://wiki.openstreetmap.org/wiki/User:Mok0#Multiplex_suggestion I think it's great. The multiplex acts sort of like a relation, except that it enforces certain constraints rather than letting people build structures which don't make logical sense. I think the concept could be extremely extensible. What do you think about implementation? From a database standpoint, it looks like a type of relation. But who enforces the constraints? Server-side would certainly best protect the data from corruption. Editor imposed constraints would be more in tune with the current OSM philosophy (let the mappers do whatever the editors let them do, and just mark logically nonsensical situations in weblint). My feeling is that it will be very hard to introduce something new that does not stick with the established philosophy. Here are my thoughts on the data structure: You are right that this is a kind of relation, but perhaps even more, it is a miniature instance of a map with an embedded shape? I guess the novel concept in an OSM context is that there are private things inside the object that the user does not have access to (or should not, of course the user can go and edit the XML). The multiplex object has a list of private nodes and ways. Some of these nodes are tagged hotspots. The private ways must start and end in a hotspot, since these are the multiplex's connection to the outer world. The object also contains a list of public nodes and ways that define the outer shape of the object, so the user is able to tweak the appearance of the object. Perhaps the positions of the hotspots as well. All nodes of the object are relative to an internal origin. When instanced on the map the internal origin is set to the actual coordinates on the world map. Probably, there is a need for a rotation/skewing operation as well, which means the object needs to store a 3x3 matrix. Any way you can think of that I might be able to help? TBH I am quite ignorant on how OSM development proceeds, how ideas are developed and how they are put into real life use. You can certainly help by enlightening me in that regard :-) Cheers, Morten ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On 26/11/2009, at 11.13, Jean-Marc Liotier wrote: Morten Kjeldgaard wrote: On 25/11/2009, at 14.11, Jean-Marc Liotier wrote: The map-drawing approach is valuable in OSM because it allows us to indicate residential areas parks, etc. However, in addition, OSM has a graph-based approach for a description of the network of roads which makes it *uniquely* valuable. Graphs prefectly represents the road map and can be used for many applications, routing is an example that many people use daily. Graph is the word I was looking for... Thanks for introducing it to the debate. Indeed the graph (nodes+edges) is the simplest way to model a network. In modeling, the simplest way is likely to be the best. But if we map everything as an area, do we lose the ability to perform graph calculations ? Can't an area be considered as a set of edges connecting all nodes inside it ? In my view it would make much more sense to work on a more expressive (perhaps BNF based?) tagging scheme. This would enable a gradual enhancement of the map, where the new tagging syntax could live along-side the old. From my OpenStreetMap novice point of view, modeling ordered sub-ways inside a highway, each with its own set of tags would go a long way toward removing the need to model ways as areas. Special cases would remain, but if for a given way I can define the order of sidewalk, bicycle lane, bus lane, car lanes, separators and whatever else, each with speed limit, width and various other tags, I barely see the need for area mapping of ways. Is there any problem with this approach ? It would introduce hierarchy and ordering, but it would reuse all the existing tags and remain compatible with the existing scheme. Notice that introducing hierarchy and ordering fits the existing OpenStreetMap XML schema quite naturally: all that would be needed is to nest a way inside a way - except that the nested way would have no nd but only tags. I'm no big XML expert, but I do know that it is an intrinsically hierachial language. However, it seems to me that the original designers of the OSM XML schema went through quite some effort to flatten it by using attributes and make it consist of lists of things. That has the great merit of making the parsers much simpler. Thinking about it, I think it's probably not realistic to change this in a fundamental way, so in that sense I have to rescind my former comments about a BNF formulated language :-) However, it is possible to achieve an hierachical data-structure using lists of lists, and so in that way I think there's more promise in the discussion about the multiplex objects in another sub-thread of this thread. You yourself actually suggested something similar AFAICS. Cheers, Morten ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Thu, Nov 26, 2009 at 5:26 PM, Jean-Marc Liotier j...@liotier.org wrote: Maybe lines and areas each serve a different purpose : areas describe the physical layout of the world whereas lines describe navigation paths. So maybe the debate should be re-framed as whether OpenStreetMap wants to be a database limited to navigational uses or a physically correct map. Navigation is a S.M.A.R.T (Specific, Measurable, Attainable, Relevant, Tangible) goal whereas complete description of the physical layout of the world is a more abstract goal I think it's pretty obvious by this stage that OSM is more than just for navigational uses. And I think it's too late to try to restrict it back to just that. So I think the ability to map roads as directed areas is worth looking into - this seems to me to be the only problem raised so far about the original poster's question, i.e. mapping everything as areas (are there others?). For directed areas, I actually quite like Teemu's idea of using an ordered set of node-pairs. Any issues with that, or alternatives? Re: Morten's suggestion of a multiplex, is that just for intersections? If not, could you explain how you would use a multiplex to map a road or lane as a directed area? ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Roy Wallace wrote: Re: Morten's suggestion of a multiplex, is that just for intersections? If not, could you explain how you would use a multiplex to map a road or lane as a directed area? It's for everything that you'd like to draw as an area, but that needs to connect to the road network. It maintains the connectivity and thus works with routing algorithms. Cheers, Morten ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
[OSM-talk] Mapping everything as areas
Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Mapping the crossing of two roads, four cycleways and four sidewalks all as surfaces requires about twenty times as many nodes as mapping the crossing of two linear roads. That is a hefty increase in complexity, especially when having to deal with the modification of existing ways. Should that be put forward as a best practice ? When dealing with pedestrian plazas and their surroundings, the value added by area mapping makes it worthwhile, but for more standard street grids I'm not sure if that should be a priority. My geeky nitpicky self makes me want to do it, but maybe I should focus my energy somewhere else where it would be more useful. And maintaining that complexity may be more costly than what we have now. So what is your opinion ? Generalized area mapping is the future, but should we wholeheartedly embrace it right now or wait for more sophisticated tools for maintaining it and a clearer business case ? ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, 25 Nov 2009 14:11:29 +0100, Jean-Marc Liotier j...@liotier.org wrote: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Not really. At least not this or next year. That is the realm of city-planing where you need to know the number of stones to pave a sidewalk. We have a road-map. And...btw..nowhere near the accuracy required to map the width of sidewalks, space between sidewalk and road,... Marcus ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
2009/11/25 Jean-Marc Liotier j...@liotier.org: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Mapping the crossing of two roads, four cycleways and four sidewalks all as surfaces requires about twenty times as many nodes as mapping the crossing of two linear roads. That is a hefty increase in complexity, especially when having to deal with the modification of existing ways. Should that be put forward as a best practice ? When dealing with pedestrian plazas and their surroundings, the value added by area mapping makes it worthwhile, but for more standard street grids I'm not sure if that should be a priority. My geeky nitpicky self makes me want to do it, but maybe I should focus my energy somewhere else where it would be more useful. And maintaining that complexity may be more costly than what we have now. So what is your opinion ? Generalized area mapping is the future, but should we wholeheartedly embrace it right now or wait for more sophisticated tools for maintaining it and a clearer business case ? It is very interesting question. I like to do micro mapping myself and I have thought lot of business uses for it, but more or less I see it as evolutionary thing. First of all, for area I map I would like to see generalized stuff which is useful now - roads with proper tagging and directions, bus stops, public transport routes, house numbers, etc. This is what I would call first level. Second would be add paths and sizes of the roads like this. And third would be area based mapping mentioned in your message. I would like to see first level completed for 80% for selected region before moving to second and third. Also resource issues (high resolution ortphotos, sathotos, local plans) plays a role if micro mapping is possible for this region. Cheers, Peter. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 13:11, Jean-Marc Liotier j...@liotier.org wrote: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? It's good to see that I've stirred up some discussion on the issue, that was the intent. Generally speaking if you or anyone else wants to go for something topical with OpenStreetMap that interests you should just do it, whether that something mapping highways, mountain ranges or everything as an area. If you pick your tags carefully you can add areas to everything in your city and not clash with anyone else's use of the data. If you want to experiment with this you can do so now by editing e.g. Rottnest island, it's small and has z23 imagery from NearMap you can use: http://osm.org/go/swwdZ5u-- However I agree with others in this thread that this isn't something we should be generally recommending to people. For most uses of the map it's just fine to have points and lines to represent POIs and ways. It's only if you want to do fringe things like accurately model a pedestrian intersection that area mapping gives you anything tangible for your efforts. It's also worth pointing out that we're already doing area mapping, just not for everything. We try to map things like landuse, buildings, sports pitches etc. as areas, mapping smaller and smaller things as areas is a natural progression from what we're currently doing. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 8:11 AM, Jean-Marc Liotier j...@liotier.org wrote: Mapping the crossing of two roads, four cycleways and four sidewalks all as surfaces requires about twenty times as many nodes as mapping the crossing of two linear roads. That is a hefty increase in complexity, especially when having to deal with the modification of existing ways. Should that be put forward as a best practice ? Isn't it better in most situations to have both (ways and areas) rather than just one or the other? At an intersection, yes, there is one squarish section of road that I am capable of traveling on in any spot in any direction. But the actual paths of travel through that intersection form intersecting lines, not areas. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Jean-Marc Liotier wrote: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Imo, area mapping is too advanced for now. After all, - it's quite hard to get the data (several width measurements required) - there aren't many practical applications - you can't work around some editing problems with shared nodes anymore - we don't have software support for it As the next step for areas where most of the basics are done, I'd rather start lane mapping. It has some very attractive use cases (detailed routing instructions for cars, routing and maps for pedestrians/bicycles) and it's relatively easy to gather the data (you just look at the street, no tools required - not even a GPS). Actually, I don't believe most mappers will be able and willing to produce data that is more precise than what can represented with width tag + lane info any time soon. Of course, if you *want* to map areas in addition to linear road representations, just do it. Tobias Knerr ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Thu, Nov 26, 2009 at 1:51 AM, Anthony o...@inbox.org wrote: Isn't it better in most situations to have both (ways and areas) rather than just one or the other? At an intersection, yes, there is one squarish section of road that I am capable of traveling on in any spot in any direction. But the actual paths of travel through that intersection form intersecting lines, not areas. This raises another interesting question, that is, whether highways=* should *necessarily* express logical paths of travel, or whether they are just a convenient way to represent an *area* used as a path of travel, as a placeholder for future, more detailed mapping (e.g. as an area). I'm not convinced that, say, a road should be mapped as *both* a way and an area - I don't see any need for that. But I guess you could map an intersection as an area and the paths of travel that pass through it as ways - if you want... Mixing and matching - that is, using *whatever most appropriately captures reality* in that particular case - is part of the beauty of OSM. That said, in reality, features that are 2D *are* areas, and should *eventually* be mapped as such in OSM. But I don't think there's any rush. Using ways with width=* is a good, quick, interim solution. Where you have the time, sure, go ahead and map areas. I do think we will need some more discussion and documentation about mapping areas - remember the debate about that keeps coming up, about whether adjacent areas should share nodes? ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 4:59 PM, Roy Wallace waldo000...@gmail.com wrote: I'm not convinced that, say, a road should be mapped as *both* a way and an area - I don't see any need for that. If the road doesn't have a constant width you basically need an area. Now, how are you going to indicate a direction of travel on an area? I guess you could come up with some way to do it, but you'd basically be defining a way. That said, in reality, features that are 2D *are* areas, and should *eventually* be mapped as such in OSM. But I don't think there's any rush. Using ways with width=* is a good, quick, interim solution. Where you have the time, sure, go ahead and map areas. I agree. Even if you just map the area and don't put any tags on it (or put note=some textual description of what you just mapped). I do think we will need some more discussion and documentation about mapping areas - remember the debate about that keeps coming up, about whether adjacent areas should share nodes? I didn't know that was up for debate. I thought the consensus was that they should not only share nodes, but they should share ways as well. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
2009/11/25 Tobias Knerr o...@tobias-knerr.de Jean-Marc Liotier wrote: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Imo, area mapping is too advanced for now. After all, - it's quite hard to get the data (several width measurements required) well depends on the quality you want to achieve (can do it with aerial images just now) and on the sources you have (you can use open sources like in Germany Bebauungsplan, site plans you own the rights, etc.). - there aren't many practical applications there is one key application: rendering - you can't work around some editing problems with shared nodes anymore don't understand what you intend - we don't have software support for it you simply add area=yes to your closed way. The only thing: don't delete the current centre-ways. Maybe it would be best to tag the road-areas as landuse=road instead of highway=something to avoid conflicts. As the next step for areas where most of the basics are done, I'd rather start lane mapping. It has some very attractive use cases (detailed routing instructions for cars, routing and maps for pedestrians/bicycles) and it's relatively easy to gather the data (you just look at the street, no tools required - not even a GPS). yes sure, but A doesn't exclude B. Actually, I don't believe most mappers will be able and willing to produce data that is more precise than what can represented with width tag + lane info any time soon. no problem, who wants to do it, can do it. Look here: http://www.openstreetmap.org/?lat=51.300723lon=11.427789zoom=18layers=B000FTF Of course, if you *want* to map areas in addition to linear road representations, just do it. +1 cheers, Martin ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
2009/11/25 Anthony o...@inbox.org I didn't know that was up for debate. I thought the consensus was that they should not only share nodes, but they should share ways as well. no, I don't think that's a good idea as the resulting multipolygons make the situation unnecessarily complicated. cheers, Martin ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 5:21 PM, Martin Koppenhoefer dieterdre...@gmail.com wrote: 2009/11/25 Anthony o...@inbox.org I didn't know that was up for debate. I thought the consensus was that they should not only share nodes, but they should share ways as well. no, I don't think that's a good idea as the resulting multipolygons make the situation unnecessarily complicated. Wow. I hope you're in the minority on that one, because now that I discovered multipolygon relations there's no way I'm going back to mapping the exact same line three times (e.g. to represent a park adjacent to a residential area separated by a fence). ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Martin Koppenhoefer schrieb: 2009/11/25 Tobias Knerr o...@tobias-knerr.de Jean-Marc Liotier wrote: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? Imo, area mapping is too advanced for now. After all, - it's quite hard to get the data (several width measurements required) well depends on the quality you want to achieve (can do it with aerial images just now) [...] That's an additional requirement, though, so it's not possible everywhere. - there aren't many practical applications there is one key application: rendering For most maps (or most zoom levels of most maps), it's not that useful to use real outlines for ways. A linear abstraction with exaggerated (and possibly importance-dependent) widths is common and usually more practical. - you can't work around some editing problems with shared nodes anymore don't understand what you intend There have been several discussions whether area borders - such as landuse areas - should use the same nodes as streets they are adjacent to. Iirc, some participants complained that sharing nodes causes editing problems - making it hard to select individual ways, requiring the relatively unknown unglue operations when editing the ways etc. With streets represented as areas, the way=middle-of-the-road argument wouldn't apply, so we probably would have to start dealing with overlapping ways and/or shared nodes. (I'm not necessarily saying this is a valid concern, I just remember it being raised. I assumed that shared nodes would remind everyone of those recurring discussions - apparently, that wasn't correct.) - we don't have software support for it you simply add area=yes to your closed way. Which won't be supported properly by renderers (for many highway types - and not at all for directional features like steps or oneways) or routing applications (it might use the outline of the area, which is equivalent to ignoring the area=yes). A simple area=yes could even be considered wrong. I'd interpret a highway=* area with area=yes is an area where there's no regulated direction of traffic. There should be an easy way to identify areas which are outlines of ways so you can decide not to draw these. After all, abstracting roads to lines with uniform, non-realistic width can be a sensible design decision. (See above.) Even if you believe it would be correct, there would still be problems with directional features, left/right/forward/backward tags etc. Therefore, I think this statement is very important: The only thing: don't delete the current centre-ways. Maybe it would be best to tag the road-areas as landuse=road instead of highway=something to avoid conflicts. As the next step for areas where most of the basics are done, I'd rather start lane mapping. It has some very attractive use cases (detailed routing instructions for cars, routing and maps for pedestrians/bicycles) and it's relatively easy to gather the data (you just look at the street, no tools required - not even a GPS). yes sure, but A doesn't exclude B. Not at all. I'm just stating my personal preferences. Of course, the perfect solution is to map everything. Actually, I don't believe most mappers will be able and willing to produce data that is more precise than what can represented with width tag + lane info any time soon. no problem, who wants to do it, can do it. Look here: http://www.openstreetmap.org/?lat=51.300723lon=11.427789zoom=18layers=B000FTF That's interesting! Luckily, a single example doesn't prove my most mappers statement wrong yet. ;) Tobias Knerr ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Hi, Anthony wrote: Wow. I hope you're in the minority on that one, because now that I discovered multipolygon relations there's no way I'm going back to mapping the exact same line three times (e.g. to represent a park adjacent to a residential area separated by a fence). That's certainly the way multipolygons are intended to be used - *especially* in situations where there cannot, by definition, be a no man's land between neighbouring polygons, e.g. when talking (most types of) boundaries. Bye Frederik -- Frederik Ramm ## eMail frede...@remote.org ## N49°00'09 E008°23'33 ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 6:07 PM, Martin Koppenhoefer dieterdre...@gmail.com wrote: 2009/11/25 Anthony o...@inbox.org I didn't know that was up for debate. I thought the consensus was that they should not only share nodes, but they should share ways as well. no, I don't think that's a good idea as the resulting multipolygons make the situation unnecessarily complicated. Wow. I hope you're in the minority on that one, because now that I discovered multipolygon relations there's no way I'm going back to mapping the exact same line three times (e.g. to represent a park adjacent to a residential area separated by a fence). OK, I put that right (as I'm using multipolygons myself quite a lot): it depends on the situation. If the fence (line between the 2 areas) is consisting of a lot of nodes it might be better to use a multipolygon, but if its just 2-3 nodes, I bet you will never be faster with a relation. You will still be creating the first multipolygon when I already finished all polygons ;-) Whew, you scared me. Personally, I mostly use Potlatch, and don't find relations to be much effort at all (and much easier for later editing), but I'm perfectly willing to cooperate with people who do it the other way. Eventually, one day, I guess we'll have to decide, but not until all the editors make one way or the other a piece of cake, and not until a script is in place to convert all the instances of the losing method into the winning method. By that time we'll have every single area of the globe (except maybe the oceans) covered by an area, right? :) ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 6:13 PM, Tobias Knerr o...@tobias-knerr.de wrote: There have been several discussions whether area borders - such as landuse areas - should use the same nodes as streets they are adjacent to. Iirc, some participants complained that sharing nodes causes editing problems - making it hard to select individual ways, requiring the relatively unknown unglue operations when editing the ways etc. With streets represented as areas, the way=middle-of-the-road argument wouldn't apply, so we probably would have to start dealing with overlapping ways and/or shared nodes. I'm one of the ones who objects to landuse areas sharing the same nodes as streets they are adjacent to. But my objection would go away if the street were mapped as an area. Sort of. In my opinion the residential landuse area shouldn't include the sidewalk either, or even the unpaved right of way if there is no sidewalk. Yes, it'd be a pain to edit with overlapping ways and/or shared nodes. But that's why God made multipolygon relations :). ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
2009/11/26 Anthony o...@inbox.org losing method into the winning method. By that time we'll have every single area of the globe (except maybe the oceans) covered by an area, right? :) or even by several areas and inside even more boundaries... ;-) cheers, Martin ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Wed, Nov 25, 2009 at 6:41 PM, Martin Koppenhoefer dieterdre...@gmail.com wrote: 2009/11/26 Anthony o...@inbox.org losing method into the winning method. By that time we'll have every single area of the globe (except maybe the oceans) covered by an area, right? :) or even by several areas and inside even more boundaries... ;-) Sure, we've gotta have highway=lane (way) inside ground_cover=roadway (area) inside landuse=highway (area) Along with ground_cover=sidewalk; ground_cover=grass; barrier=curb; etc. :) ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Thu, Nov 26, 2009 at 8:09 AM, Anthony o...@inbox.org wrote: Now, how are you going to indicate a direction of travel on an area? I guess you could come up with some way to do it, but you'd basically be defining a way. Good point. Anyone got ideas on this? Maybe it is indeed necessary to map each highway as a way (to indicate a logical path of travel) as well as an area (to reflect reality!). ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Thu, 26 Nov 2009 02:40:53 +0200, Roy Wallace waldo000...@gmail.com wrote: On Thu, Nov 26, 2009 at 8:09 AM, Anthony o...@inbox.org wrote: Now, how are you going to indicate a direction of travel on an area? I guess you could come up with some way to do it, but you'd basically be defining a way. Good point. Anyone got ideas on this? Maybe it is indeed necessary to map each highway as a way (to indicate a logical path of travel) as well as an area (to reflect reality!). A while ago I had an idea of lane type for osm, which is a directed area. I think a picture will explain it better: http://elanor.mine.nu/daeron/types.png (also includes an area type). The lane type would consist of an ordered list of node pairs. Optionally the first and last pair could contain a null node, to allow mapping a lane that branches off from another. Also maybe other pairs could contain nulls, to avoid unnecessary nodes. That way the area would have a direction, and it would be unnecessary to use ways to indicate the direction in addition to the area. This of course would need pretty major reworking of the database, editors and renderers... Regards Teemu Koskinen ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
On Nov 25, 2009, at 4:40 PM, Roy Wallace wrote: On Thu, Nov 26, 2009 at 8:09 AM, Anthony o...@inbox.org wrote: Now, how are you going to indicate a direction of travel on an area? I guess you could come up with some way to do it, but you'd basically be defining a way. Good point. Anyone got ideas on this? Maybe it is indeed necessary to map each highway as a way (to indicate a logical path of travel) as well as an area (to reflect reality!). I think it will be necessary to retain both lines and areas, but in different data sets. I think this is true for a lot more than just highways, actually. It also sidesteps some of the geometric gymnastics made necessary by using large-scale geographic data at lower zoom levels. These are two slides from a talk I gave on OpenStreetMap to the North American Cartographic Information Society last month: http://teczno.com/s/3jb http://teczno.com/s/c96 (full talk here: http://teczno.com/s/l05) The first slide shows now-gone image from the Ordnance Survey website illustrating map detail at a number of scales. This thread is about the scales to the right of the illustration, 1:10k or so and below. At that scale, roads aren't lines anymore, they're areas and should be treated as such. You're no longer routing people *along* a road, instead you're moving them through and across the road, into buildings, etc. Stefan Knecht's United Maps is one company that's thinking about data at this scale. OSM data is not suitable for use at 1:10K and below, because it's designed and optimized for typical city scales: 1:250K down to 1:25K. That's a pretty wide range for a single data set, but it's starting to shear a bit. The second slide is a call for help - in order to be usable at and above 1:250K (cities, regions, states), the data will require editing at a different scale, one that simplifies river areas to lines, dual carriageways into single ways, collections of streets into urban polys, shopping areas to points, etc. With the impending release of Natural Earth Vector, we're going to have a really good data set at the far left end of the scale above 1:10m. That leaves a critical gap between 1:10m and 1:250K, quite a wide swath. The use of rasterization libraries like Mapnik and Osmarender papers over this gap somewhat by doing the expensive rendering process just once on the server, but it's slow and redundant. I've done some recent work with OSM that addresses it as vectors and the data is basically useless when you've zoomed out a bit. My sense is that OSM will need to expand its scale coverage in two directions, and possibly develop a concept of trans-scale relations. I've seen this in other vector sets before, e.g. ones that have a layer for lake shapes vs. lake centerlines like Natural Earth promises. Potlatch 1.3 makes it possible to edit down into the 1:1K scale where it would be appropriate to model highways are areas, but the question of travel direction on these highways is irrelevant - if you want to route someone, you use the lower zoom of today's existing OpenStreetMap, which is created at a scale where roads are ways. On the left side of the scale, I think it will be necessary to have two separate, low-scale OSM data sets that use higher-scale renderings as input. These datasets, which could simply be separate instances of OSM, would be much smaller and simpler, and optimized for vector manipulation of large areas. In simple OSM, highways would be single ways with local features such as bridges omitted, local POIs like schools or hospitals would be points, buildings would disappear, etc. In an even lower-scale mini OSM, smaller local roads would simply disappear in favor of built-up areas, trunk roads and motorways would be a single classification, rivers would be lines, most local POIs would be omitted, and so on. The data set / zoom level breakdown might look like this: 6 - Nat. Earth http://osm.org/go/TZNQp-- 7 mini OSMhttp://osm.org/go/TZNQp 8 mini OSMhttp://osm.org/go/TZNQpm- 9 mini OSMhttp://osm.org/go/TZNQp0-- 10 simple OSM http://osm.org/go/TZNQns 11 simple OSM http://osm.org/go/TZNQnsO- 12 simple OSM http://osm.org/go/TZNQnp9-- 13 current OSM http://osm.org/go/TZNQnp9 14 current OSM http://osm.org/go/TZNQp1hY- 15 current OSM http://osm.org/go/TZNQp1hC-- 16 current OSM http://osm.org/go/TZNQp1hC 17 current OSM http://osm.org/go/TZNQp1hC6- 18+ maxi OSMhttp://osm.org/go/TZNQsgND_-- My sense is that such a project would require only the setup of an additional two, lower-capacity OSM servers and probably the creation of a new rendering stylesheet. It'd be interesting to tackle feature equivalence at
Re: [OSM-talk] Mapping everything as areas
2009/11/25 Jean-Marc Liotier j...@liotier.org: Ævar Arnfjörð Bjarmason's diary entry last week (http://j.mp/8ESP8o) stired my interest. Using a few examples, he showed how mapping everything as an area - or as a volume - makes ultimate sense. Should we go for it now ? The main usage for this that I see would be neat rendering. I'm not saying that's bad, rendering is important. But I think personally I'm going to wait for the real thing, a project to make a 3D model of the whole earth, really our world is not two-dimensional and it seems like a waste of time to put a lot of effort into the intermediate step between the street map and the model of the world. When I started mapping I made a point of adding the storeys count or height info for all buildings I drew with the intent to try a conversion to 3D at some point, later mapsurfer.net made me really happy by rendering the building heights before I had time to implement my idea. But the geeky part tells me it's a band-aid. Google got it with the crowd-sourcing of building models, but I think they don't have enough crowd-sourcing power yet to make the project take off and obviously they don't get it about open licensing and stuff. A couple of years ago there was also a project supported the Madrid municipality, Spain, to build a 3D model of the whole city with textures and stuff, but I don't know what came out of it. Now that microsoft and others have shown demos where they reconstruct models from a huge load of touristic pics or from recording with a special camera on google-street-view-like cars, I think we're close to be able to start such a project, with people building the necessary hardware like they build the RC planes to do aerial photography now, and the armchair mappers crowds filling in the details of the model, that's my vision anyway. Cheers ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Mapping everything as areas
Michal Migurski wrote: I think it will be necessary to retain both lines and areas [..] Maybe lines and areas each serve a different purpose : areas describe the physical layout of the world whereas lines describe navigation paths. So maybe the debate should be re-framed as whether OpenStreetMap wants to be a database limited to navigational uses or a physically correct map. Navigation is a S.M.A.R.T (Specific, Measurable, Attainable, Relevant, Tangible) goal whereas complete description of the physical layout of the world is a more abstract goal To make a workable model, there has to be a degree of abstraction. The question is to chose the right one... ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
