Re: [OSM-talk] Road cores and casings on standard Mapnik rendering
On 1/21/2012 12:05 AM, Ben Robbins wrote: http://wiki.openstreetmap.org/w/images/2/21/Comparison_-_Junction1.png Just a minor issue - shouldn't the primary_link and unclassified near the upper right corner be motorway_links, since you can only access them from the motorway? Otherwise, this is basically how I tag (though (a) I don't name links and (b) I'd probably change the northwest-southeast road to secondary where the ramps come off). ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Road cores and casings on standard Mapnik rendering
On 1/21/2012 6:03 AM, Richard Mann wrote: The current tagging rules for links don't make life at all easy for the renderer, but I got flamed when I suggested that the link road should take the status of the lower classification (unless it's a motorway_link). I agree that taking the status of the lower makes sense if it's a typical intersection bypass (right turn in the US, left turn in the UK). But if e.g. a trunk has a full motorway-style interchange with a lower-classification road, I'll use trunk_link. ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Road cores and casings on standard Mapnik rendering
The current tagging rules for links don't make life at all easy for the renderer, but I got flamed when I suggested that the link road should take the status of the lower classification (unless it's a motorway_link). It's compounded with various problems with how Mapnik handles layers and bridges. So instead I add links_lower and links_higher tags, and render (both order and colour) on the basis of the contents of the links_lower tag. Perhaps the rendering gods prefer Mapnik to be a bit crap, so cartographers can add value by doing something better. Who knows. Richard On Sat, Jan 21, 2012 at 5:13 AM, Ben Robbins ben_robbi...@hotmail.comwrote: Another Failed Link. Try this: http://wiki.openstreetmap.org/w/images/6/6a/Z18crop.png ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
[OSM-talk] Road cores and casings on standard Mapnik rendering
Hi, I'm copying this message over from help.openstreetmap.org (http://help.openstreetmap.org/questions/10088/mapnik-rendering-road-cores-and-casings) which is unsuitable for discussions. It is written by user Ben, and I have closed the question on help and requested a move to the mailing list. -- Hi, In short I'm wondering if someone would be able to have a look at the mapnik rule sheet on road widths, in regards to what I shall elaborate on. I have done about as much as I am able to do myself. On the Mapnik renders there are a few differences in the road widths which I would like to propose getting a bit of a tweaking. I haven't looked at the rulesheet itself for a couple of reasons, so I started by making a test area for the different zoom levels for the road combinations. (excluding _link being down the central line). (all these links are having the underscore dropped before the last - because it seems to be the italic shortcut) http://wiki.openstreetmap.org/w/images/1/14/Core-Casing_-Z13.png http://wiki.openstreetmap.org/w/images/0/02/Core-Casing-Z14.png http://wiki.openstreetmap.org/w/images/2/21/Core-Casing-Z15.png http://wiki.openstreetmap.org/w/images/e/e5/Core-Casing-Z16.png http://wiki.openstreetmap.org/w/images/5/55/Core-Casing-Z17.png http://wiki.openstreetmap.org/w/images/4/40/Core-Casing-_Z18.png From this I have extracted estimations the core-casing values and put them here: http://wiki.openstreetmap.org/wiki/User:Ben./MapnikRoads (These are estimates, so may not always be correct, but it makes it clear where the differences are) So then I stuck them into this table: http://wiki.openstreetmap.org/w/images/0/02/Difference_in_Core-Casing.PNG To evaluate: The motorway and motorway_link_ are the strangest as they are smaller than all but a few roads of lower status than them. Then from trunk to Secondary the roads are a fraction bigger than others, but more noticeable the casing is thinner. Thirdly the way they increase over zoom levels isn't smooth at times. Finally the order in which they render has links render very early, rather than just before there similarly named road (i.e. motorway_link to motorway). The main issue with this is in flyover junctions where roads don't flow nicely into one another; but there are other reasons also. In conclusion: The answer to this is a bit opinionated so there isn't really one, but the suggestion I would make is that either all roads bar maybe residential and service should be the same size with the same casing, maybe oneday having lanes= taken into consideration. Another option is to have all roads under and including tertiary as the same along with all _link roads being the same. Then all roads at secondary and above levels being steped up bigger. This section would be good to discuss though for the better idea. cheers, Ben ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Road cores and casings on standard Mapnik rendering
* Frederik Ramm frede...@remote.org [2012-01-20 09:16 +0100]: So then I stuck them into this table: http://wiki.openstreetmap.org/w/images/0/02/Difference_in_Core-Casing.PNG That is an excellent reference. Thanks! The motorway and motorway_link_ are the strangest as they are smaller than all but a few roads of lower status than them. I don't know for certain but I figured this was because motorways are almost always in pairs and the thinness is a compensation for that doubling. Finally the order in which they render has links render very early, rather than just before there similarly named road (i.e. motorway_link to motorway). I think the links should render before all roads residential and up (possibly before service, too); IMHO, you get better-looking results that way. The main issue with this is in flyover junctions where roads don't flow nicely into one another; but there are other reasons also. There are some issues with bridge rendering at the moment, in particular that _link roads on bridges are *not* rendered as early as non-bridge _link roads. I've a mind to sort out the things about layered rendering that bother me at the upcoming DC hack weekend and then submit a patch. Can you give an example of a junction that doesn't look good to you? In conclusion: The answer to this is a bit opinionated so there isn't really one, but the suggestion I would make is that either all roads bar maybe residential and service should be the same size with the same casing More prominent roads should be wider, I think, but the casings should be consistent, yes. maybe oneday having lanes= taken into consideration. My opinion is that lanes= would be better for a specialized rendering, rather than the main map, because I think road thickness should be correlated to road prominence, and using lanes= could lead to inversions of that rule in places. One of my favorite renderings is TopOSM: http://toposm.com/us/index.html Its rules are very consistent and I like its progression of road widths. -- ...computer contrarian of the first order... / http://aperiodic.net/phil/ PGP: 026A27F2 print: D200 5BDB FC4B B24A 9248 9F7A 4322 2D22 026A 27F2 --- -- Sendmail may be safely run set-user-id to root. -- Eric Allman, Sendmail Installation Guide --- -- ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Road cores and casings on standard Mapnik rendering
Can you give an example of a junction that doesn't look good to you? The z13-z18 links I previously gave seem not all to open, so instead here is a cropped z18 sections:http://wiki.openstreetmap.org/wiki/File:Z18crop.pngIt best shows the common problems, coming from the core-casing width issue. Below is a junction which I made as neat as I could but didn't touch the highway= tags. This is how it was added, and how all the junctions I've seen have been around Dubai tend to be mapped, and most of the world, where I’ve edited. At the bottom left there is an example of the issue of there not being a service_link tag, or just that the motorway_link renders early. However I do see your point, and if the _link tags were later there would be other issues gained for those dealt with. http://wiki.openstreetmap.org/w/images/2/21/Comparison_-_Junction1.png Now if we say that a road only moves 'up' in status when it joins a higher status road and not before, then I end up with this: (I have now started to map for the renderer, although I can see justification in this in reality, where link has to meet it’s higher ranking ‘parent’ before it becomes that status.) http://wiki.openstreetmap.org/w/images/0/07/Comparison_-_Junction2.png An issue here is the lack of an unclassified_link road, so in the top left the road sits on top of motorway_link.If I say that all departing roads must also drop to the status of the road they are linking where that road is lower status, and have no actual _link roads then I get this: http://wiki.openstreetmap.org/w/images/8/8f/Comparison_-_Junction3.png If I go back 1 step, but remove all 'link' status tags, I get this: http://wiki.openstreetmap.org/w/images/1/19/Comparison_-_Junction4.png So, this really brings up 3 separate considerations, and the rendering is a small fraction of it, and I'm going to try to explain what’s in my head in a clear way... here goes! If all road statuses don't increase before meeting a higher road status; and all road status's decrease, when leaving another road, in preparation for there end-connection road status, then it works on the usage of no ‘links’. If links are used, then all status's must have a link variant. This is currently not so. In the event of this not being possible, due to ‘reality’ dictating road status, and therefore going against the aforementioned criteria so as to ‘map how it is’, then ‘links’ would again have to be available for all variants. However in the event of a none-‘link’ road coming off a ‘link’ road of higher status, it would need to devolve to a none ‘link’ road, which would be messy. However common practice has the road status as increasing to meet the fore-coming road status where it is higher, and holds onto former road status, again where it is higher. So the factors causing this are: Standard editing practice – Having roads promoted to the higher of its options.Missing _link values for the smaller road types.Different Rendering Widths. This also brushes on ‘map how it is, not how it renders’, but then we should also ‘map so it may render how it is.’ And here in lies the clash. One of my favorite renderings is TopOSM: http://toposm.com/us/index.html Its rules are very consistent and I like its progression of road widths. Nice, haven't seen this before, thanks for that. Cheers, Ben ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Road cores and casings on standard Mapnik rendering
Another Failed Link. Try this: http://wiki.openstreetmap.org/w/images/6/6a/Z18crop.png ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
