Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On Fri, Mar 21, 2014 at 05:05:21PM -0500, Paul Johnson wrote: On Mar 21, 2014 4:59 PM, Richard Z. ricoz@gmail.com wrote: Example of a problem this should catch: I have seen cases where someone wanted to tag a simple bridge with layer and added the layer to the wrong segment - tagging a hundred or more miles of road accidentally, possibly affecting crossings far away for an area not downloaded. The validator will not detect it and in most cases the renderer will work around this bug very well so it is only discovered by accident in most cases. This is not limited to layer, I have seen the same problem with culverts and bridges. This seems like something a validator should be able to catch without overly complicating how levels work. I am not trying to complicate how layers work right now but trying to codify how they already work in 99% of cases in easy to follow rules that could be utilised by validators. Yes, the validator should be able to catch such situations. Just how? It doesn't right now. I see some possible approaches: * warn user if tagging excessively long ways with layer. Here the problem is to judge what is excessively long. * warn user if applying layer to a way that exceeds the size of downloaded area because in this situation the validator is unable to do even the basic checks. * warn user if applying layer to a way without tunnel/bridge/covered/indoor or similar tags. There is more than just JOSM and all should follow the same rules so ideally this rules would be nicely documented in the wiki. What kind of underground areas are that in Kansas, do you have a pointer? I'm not exactly sure where exactly it is, but there's apparently a pretty extensive underground industrial and office district entirely underground complete with drivable underground streets in KCK thanks to repurposing an old mine. interesting, I will have a look when I have some time. Richard ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On 22.03.2014 11:01, Richard Z. wrote: On Fri, Mar 21, 2014 at 05:05:21PM -0500, Paul Johnson wrote: On Mar 21, 2014 4:59 PM, Richard Z. ricoz@gmail.com wrote: Example of a problem this should catch: I have seen cases where someone wanted to tag a simple bridge with layer and added the layer to the wrong segment - tagging a hundred or more miles of road accidentally, possibly affecting crossings far away for an area not downloaded. The validator will not detect it and in most cases the renderer will work around this bug very well so it is only discovered by accident in most cases. This is not limited to layer, I have seen the same problem with culverts and bridges. This seems like something a validator should be able to catch without overly complicating how levels work. I am not trying to complicate how layers work right now but trying to codify how they already work in 99% of cases in easy to follow rules that could be utilised by validators. Yes, the validator should be able to catch such situations. Just how? It doesn't right now. I see some possible approaches: * warn user if tagging excessively long ways with layer. Here the problem is to judge what is excessively long. As judgement is difficult and it will still depend on other cases, I do not think this will help that much * warn user if applying layer to a way that exceeds the size of downloaded area because in this situation the validator is unable to do even the basic checks. even though this will lead to false warnings when working with incomplete data, I would give this solution a try. * warn user if applying layer to a way without tunnel/bridge/covered/indoor or similar tags. Covered is an example where it does not work e.g. you tag the building=roof with layer and not the way underneath. Still for other tags (bridge/tunnel etc) this would be helpful. There is more than just JOSM and all should follow the same rules so ideally this rules would be nicely documented in the wiki. +1 Note, JOSM would almost be able to use the list right now, already. What kind of underground areas are that in Kansas, do you have a pointer? I'm not exactly sure where exactly it is, but there's apparently a pretty extensive underground industrial and office district entirely underground complete with drivable underground streets in KCK thanks to repurposing an old mine. interesting, I will have a look when I have some time. Could you post a link, please. I wonder how mapnik will work with that as there are already problems with a single underground floor/parking. signature.asc Description: OpenPGP digital signature ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On Sat, Mar 22, 2014 at 03:33:03PM +0100, colliar wrote: On 22.03.2014 11:01, Richard Z. wrote: On Fri, Mar 21, 2014 at 05:05:21PM -0500, Paul Johnson wrote: On Mar 21, 2014 4:59 PM, Richard Z. ricoz@gmail.com wrote: Example of a problem this should catch: I have seen cases where someone wanted to tag a simple bridge with layer and added the layer to the wrong segment - tagging a hundred or more miles of road accidentally, possibly affecting crossings far away for an area not downloaded. The validator will not detect it and in most cases the renderer will work around this bug very well so it is only discovered by accident in most cases. This is not limited to layer, I have seen the same problem with culverts and bridges. This seems like something a validator should be able to catch without overly complicating how levels work. I am not trying to complicate how layers work right now but trying to codify how they already work in 99% of cases in easy to follow rules that could be utilised by validators. Yes, the validator should be able to catch such situations. Just how? It doesn't right now. I see some possible approaches: * warn user if tagging excessively long ways with layer. Here the problem is to judge what is excessively long. As judgement is difficult and it will still depend on other cases, I do not think this will help that much it is not my preferred approach either, but it might still catch some cases which might otherwise be hard to catch. For example I think it is reasonable to assume that if someone tags 200 miles of a road with layer=1 it is an accident and the rate of false positives would be very low. Could this limit be much lower without generating many false positives? For layers 2,3,4,5 it appears reasonable to assume higher limits because these are more likely to be used for longer bridges etc. * warn user if applying layer to a way that exceeds the size of downloaded area because in this situation the validator is unable to do even the basic checks. even though this will lead to false warnings when working with incomplete data, I would give this solution a try. yes, incomplete data is another problem.. fortunately people downloading partial data through overpass usually know what they are doing pretty well. * warn user if applying layer to a way without tunnel/bridge/covered/indoor or similar tags. Covered is an example where it does not work e.g. you tag the building=roof with layer and not the way underneath. in this case there is nothing to solve. However covered=yes can be used with and without layer depending on situation, so the validator should allow that. For JOSM I have the following search string to find suspicious way/layer combinations: (highway | railway=rail |waterway) -layer=0 layer=* -tunnel=* -bridge=* -culvert=yes -*=steps -*=elevator -covered=yes -indoor=yes Surely the validator could do a better job than a simple search string but I am not sure about false positives. If you look at this area http://www.openstreetmap.org/#map=18/41.88435/-87.62125 there are quite a few matches and I have no idea if all of those could be tagged somehow better? What kind of underground areas are that in Kansas, do you have a pointer? I'm not exactly sure where exactly it is, but there's apparently a pretty extensive underground industrial and office district entirely underground complete with drivable underground streets in KCK thanks to repurposing an old mine. interesting, I will have a look when I have some time. Could you post a link, please. I wonder how mapnik will work with that as there are already problems with a single underground floor/parking. Found it meanwhile.. https://en.wikipedia.org/wiki/SubTropolis https://maps.google.com/maps?ll=39.161213,-94.476242q=loc:39.161213,-94.476242hl=ent=mz=15 https://www.openstreetmap.org/?mlat=39.161213mlon=-94.476242zoom=15#map=14/39.1543/-94.4756 looks like nothing is mapped yet? Mapping it will be tricky with a handheld GPS or Bing - maybe there is some PD data available? I believe that as it is essentially an underground building it should be mapped using level instead of layer. Same for most parking lots and many similar examples. Richard ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
This seems like a solution looking for a problem than anything actually pragmatic and worth doing. It would also needlessly overcomplicate cities that have large areas underground on multiple levels, such as Kansas City. On Sat, Mar 15, 2014 at 8:44 AM, Richard Z. ricoz@gmail.com wrote: Hi, I think it would be good to agree on something... https://wiki.openstreetmap.org/wiki/Talk:Key:layer#Maximum_recommended_segment_length_of_ways_tagged_with_layer Richard ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On Fri, Mar 21, 2014 at 03:41:45PM -0500, Paul Johnson wrote: This seems like a solution looking for a problem than anything actually pragmatic and worth doing. It would also needlessly overcomplicate cities that have large areas underground on multiple levels, such as Kansas City. Example of a problem this should catch: I have seen cases where someone wanted to tag a simple bridge with layer and added the layer to the wrong segment - tagging a hundred or more miles of road accidentally, possibly affecting crossings far away for an area not downloaded. The validator will not detect it and in most cases the renderer will work around this bug very well so it is only discovered by accident in most cases. This is not limited to layer, I have seen the same problem with culverts and bridges. What kind of underground areas are that in Kansas, do you have a pointer? Richard ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On Mar 21, 2014 4:59 PM, Richard Z. ricoz@gmail.com wrote: Example of a problem this should catch: I have seen cases where someone wanted to tag a simple bridge with layer and added the layer to the wrong segment - tagging a hundred or more miles of road accidentally, possibly affecting crossings far away for an area not downloaded. The validator will not detect it and in most cases the renderer will work around this bug very well so it is only discovered by accident in most cases. This is not limited to layer, I have seen the same problem with culverts and bridges. This seems like something a validator should be able to catch without overly complicating how levels work. What kind of underground areas are that in Kansas, do you have a pointer? I'm not exactly sure where exactly it is, but there's apparently a pretty extensive underground industrial and office district entirely underground complete with drivable underground streets in KCK thanks to repurposing an old mine. ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On Sat, Mar 15, 2014 at 06:12:10PM +, moltonel 3x Combo wrote: On 15/03/2014, Fernando Trebien fernando.treb...@gmail.com wrote: I now agree that the layer tag should be used as locally as possible, so I think Richard had good intentions when proposing this. At the same time, I think you, Frederik, has a good point that arriving at a threshold for that number is quite hard. What exactly do we want to avoid? Really, really long ways with a layer tag. So why not set this threshold higher? Say 10 km? Validator rules are a good thing, but I think that length of a way that has layer=* to detect misuse of the layer tag is beside the point. Whatever threshold you use, there'll false-positives and false-negatives. How about something along the lines of negative layer but no tunnel tag (or positive/bridge) and no/too many crossing ways ? I am now thinking about unless absolutely necessary the size of objects tagged with a layer tag should not exceed a size which would be typically downloaded for editing in this area. but the wiki page already says * Tag shortest possible/practical sections of ways. Long viaducts and tunnels can be tagged with a suitable single value for their entire length for simplicity although it may sometimes be better to adjust the layer along its length to accommodate more complicated crossings. * Use the smallest suitable layer value. Only use layer=2 for a bridge that passes over a feature that is already at level 1; similarly only use layer=-2 for a tunnel that passes below another tunnel. For convenience some higher values are often locally used/reserved for very long bridges or underground networks where it is assumed that they are above/bellow most other crossings/objects in the area. - which should be good enough if people don't interpret the text in some unforseen way. Richard ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On Sat, Mar 15, 2014 at 05:12:08PM +0100, Frederik Ramm wrote: Hi, On 15.03.2014 14:44, Richard Z. wrote: I think it would be good to agree on something... https://wiki.openstreetmap.org/wiki/Talk:Key:layer#Maximum_recommended_segment_length_of_ways_tagged_with_layer I think that choosing some fixed number would be un-OSM. Your idea that length limits should apply to certain layers but not others strikes me as odd. odd - and reflecting current usage patterns as far as I can judge from analysing current data. Even odd rules can be quite useful. Thinking more about it, perhaps location=* would be a good alternative for tagging very long bridges and tunnels? Thinking of bridges spanning whole valleys with towns bellow them and similar. Working out every crossing that may happen to be bellow the long bridge and how it relates to the underground railway network down there is impractical. Richard ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
2014-03-16 12:08 GMT+01:00 Richard Z. ricoz@gmail.com: Working out every crossing that may happen to be bellow the long bridge and how it relates to the underground railway network down there is impractical. I think you are exxagerating the problem, usually this is not very complicated. Underground infrastructure will hard collide with any bridge, as it should usually get tunnel and negative layer tags while the bridges will have positive layer tags. If two bridges happen to intersect on the same layer the more advanced editors will warn you about this. Cheers, Martin ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
[OSM-talk] Maximum recommended length of ways tagged with layer
Hi, I think it would be good to agree on something... https://wiki.openstreetmap.org/wiki/Talk:Key:layer#Maximum_recommended_segment_length_of_ways_tagged_with_layer Richard ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
Hi, On 15.03.2014 14:44, Richard Z. wrote: I think it would be good to agree on something... https://wiki.openstreetmap.org/wiki/Talk:Key:layer#Maximum_recommended_segment_length_of_ways_tagged_with_layer I think that choosing some fixed number would be un-OSM. Your idea that length limits should apply to certain layers but not others strikes me as odd. You have already written down a rule that people shouldn't use layer=-1 to hide validator warnings; no need to breathe down mapper's necks with ever more detailed rules. It's not a German project ;) Bye Frederik -- Frederik Ramm ## eMail frede...@remote.org ## N49°00'09 E008°23'33 ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
I think stereotyping by nationality is quite un-OSM too. (I'm Brazilian, btw.) I think validators have a significant role in the current problem: we need a warning about missing bridges/tunnels when two ways overlap, regardless of the value in the layer tag of either way. This will discourage the use of layer=-1 on rivers to avoid validation warnings, and will also reveal when this was done and encourage people to effectively map bridges and tunnels. I now agree that the layer tag should be used as locally as possible, so I think Richard had good intentions when proposing this. At the same time, I think you, Frederik, has a good point that arriving at a threshold for that number is quite hard. What exactly do we want to avoid? Really, really long ways with a layer tag. So why not set this threshold higher? Say 10 km? On Sat, Mar 15, 2014 at 1:12 PM, Frederik Ramm frede...@remote.org wrote: Hi, On 15.03.2014 14:44, Richard Z. wrote: I think it would be good to agree on something... https://wiki.openstreetmap.org/wiki/Talk:Key:layer#Maximum_recommended_segment_length_of_ways_tagged_with_layer I think that choosing some fixed number would be un-OSM. Your idea that length limits should apply to certain layers but not others strikes me as odd. You have already written down a rule that people shouldn't use layer=-1 to hide validator warnings; no need to breathe down mapper's necks with ever more detailed rules. It's not a German project ;) Bye Frederik -- Frederik Ramm ## eMail frede...@remote.org ## N49°00'09 E008°23'33 ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk -- Fernando Trebien +55 (51) 9962-5409 The speed of computer chips doubles every 18 months. (Moore's law) The speed of software halves every 18 months. (Gates' law) ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Maximum recommended length of ways tagged with layer
On 15/03/2014, Fernando Trebien fernando.treb...@gmail.com wrote: I now agree that the layer tag should be used as locally as possible, so I think Richard had good intentions when proposing this. At the same time, I think you, Frederik, has a good point that arriving at a threshold for that number is quite hard. What exactly do we want to avoid? Really, really long ways with a layer tag. So why not set this threshold higher? Say 10 km? Validator rules are a good thing, but I think that length of a way that has layer=* to detect misuse of the layer tag is beside the point. Whatever threshold you use, there'll false-positives and false-negatives. How about something along the lines of negative layer but no tunnel tag (or positive/bridge) and no/too many crossing ways ? ___ talk mailing list talk@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk
