Re: [Tagging] Urban perimeter
2014-05-27 1:48 GMT+02:00 Fernando Trebien : > Hello everyone, > > From time to time there's a discussion in the Brazilian community on > how to tag an "urban perimeter". In Brazil, this is a legally defined > area with some defined characteristics, such as: > - different kind and level of environmental impact (and therefore > different environmental policies) > - slightly different taxation system for residents > - different maxspeed on highways (mostly determined by being inside or > outside of this perimeter) > > One user has suggested that we use settlement=yes (a proposed tag > still not voted: > http://wiki.openstreetmap.org/wiki/Proposed_features/Urban_settlements) > for that purpose. I'd like to hear your opinions and suggestions. > > Several Brazilian users have mapped the entire urban extension (not > exactly the same as the legally defined perimeter) in small cities and > tagged it using landuse=residential, which is probably wrong in most > cases and can be seen as tagging for the renderer. I believe they're > probably expecting the same visual effect one gets from Google Maps > and Here Maps: both draw a faint grey background over the urban area > and is somewhat distinguishable at the border of most cities. > (Whichever tag we go with, we would then ask rendering engine > developers to replicate that visual effect.) > I don't know in Brazil, but in Italy or Germany the maxspeed for built-up areas does not correspond perfectly with the settlement extension but is indeed yet another thing to consider. It is basically defined by street signs (start / end of a settlement according to the driving laws), and we map these signs on nodes aside the highway with traffic_sign=city_limit (name=*) and split the highway there and map the speed limit as maxspeed=50 (or whatever your default is) and source:maxspeed=IT:urban (or DE:urban etc.) http://wiki.openstreetmap.org/wiki/Key%3Asource%3Amaxspeed (we add those source:maxspeed tags so we could hypothetically adjust the speedlimit in case the law was changed, therefore we also suggest to map source:maxspeed=sign if there is an additional sign which confirms the default). For settlements (in urbanism / settlement geographic terms) my suggestion is to use place=* on an area. Please do not use landuse=residential for huge areas with all kind of landuses inside. cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
On Tue, May 27, 2014 at 7:18 AM, Martin Koppenhoefer wrote: > For settlements (in urbanism / settlement geographic terms) my suggestion is > to use place=* on an area. There is one problem when using place: people start to duplicate data. What is already present/available in the place node is duplicated in the place area. Sometimes it also causes data mismatch (population with one value in the node and a different one in the area, different classifications, names, etc). The urban perimeter tag should be as simple as possible, without giving a chance for data duplication. > Please do not use landuse=residential for huge areas with all kind of > landuses inside. Using landuse=residential is exactly what we want to avoid. ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
On Tue, May 27, 2014 at 7:18 AM, Martin Koppenhoefer wrote: > I don't know in Brazil, but in Italy or Germany the maxspeed for built-up > areas does not correspond perfectly with the settlement extension but is > indeed yet another thing to consider. It is basically defined by street > signs (start / end of a settlement according to the driving laws), and we > map these signs on nodes aside the highway with traffic_sign=city_limit > (name=*) and split the highway there and map the speed limit as maxspeed=50 > (or whatever your default is) and source:maxspeed=IT:urban (or DE:urban > etc.) > http://wiki.openstreetmap.org/wiki/Key%3Asource%3Amaxspeed (we add those > source:maxspeed tags so we could hypothetically adjust the speedlimit in > case the law was changed, therefore we also suggest to map > source:maxspeed=sign if there is an additional sign which confirms the > default). That's essentially the same as in Brazil. Mapping the perimeter would not replace mapping maxspeeds for each way individually. > For settlements (in urbanism / settlement geographic terms) my suggestion is > to use place=* on an area. Wouldn't that make users confused when reading search results? The place=* tag is already used in cities' admin centre node and (sometimes, perhaps incorrectly) admin boundary relation. > Please do not use landuse=residential for huge areas with all kind of > landuses inside. That's precisely what we want to avoid. Maybe we need a new tag for that. > cheers, > Martin > > ___ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging > -- Fernando Trebien +55 (51) 9962-5409 "Nullius in verba." ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
I like Nelson's idea of using a new value for "boundary" to represent this, mainly because the perimeter is not "ground truth" but an invisible "legal definition" that roughly matches the urbanized area. I was wondering if this concept exists elsewhere so that we can even propose such value in a way that's reusable worldwide. Here Maps represents the urban perimeter in Brazil just like this dotted line across a river near Berlin and the area inside it: http://here.com/52.5804776,13.2183974,18,0,0,normal.day But in the case of Berlin, it could be Here Maps' arbitrary choice, not a legally significant area. On Tue, May 27, 2014 at 10:01 AM, Nelson A. de Oliveira wrote: > On Tue, May 27, 2014 at 7:18 AM, Martin Koppenhoefer > wrote: >> For settlements (in urbanism / settlement geographic terms) my suggestion is >> to use place=* on an area. > > There is one problem when using place: people start to duplicate data. > What is already present/available in the place node is duplicated in > the place area. Sometimes it also causes data mismatch (population > with one value in the node and a different one in the area, different > classifications, names, etc). > > The urban perimeter tag should be as simple as possible, without > giving a chance for data duplication. > >> Please do not use landuse=residential for huge areas with all kind of >> landuses inside. > > Using landuse=residential is exactly what we want to avoid. > > ___ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging -- Fernando Trebien +55 (51) 9962-5409 "Nullius in verba." ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
2014-05-27 15:01 GMT+02:00 Nelson A. de Oliveira : > On Tue, May 27, 2014 at 7:18 AM, Martin Koppenhoefer > wrote: > > For settlements (in urbanism / settlement geographic terms) my > suggestion is > > to use place=* on an area. > > There is one problem when using place: people start to duplicate data. > What is already present/available in the place node is duplicated in > the place area. Sometimes it also causes data mismatch (population > with one value in the node and a different one in the area, different > classifications, names, etc). > It is not really duplicating data, as the place on the node does not convey any information about the spatial extension of the place. This is essentially a relic from the early days of osm, interpreting a node is easier than a relation (and relations weren't even there when we already had mapped a lot of places). The nodes convey a different info though, that of a "central spot", useful for rendering and for generic routing (without a specific address) or for computing distance tables. The solution on the long run could be to have place relations to combine the area with the place node. Duplicating data like population should be avoided, I agree. These are all well known issues, but it takes some time to sort this out. cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
2014-05-27 15:37 GMT+02:00 Fernando Trebien : > I like Nelson's idea of using a new value for "boundary" to represent > this, mainly because the perimeter is not "ground truth" but an > invisible "legal definition" that roughly matches the urbanized area. > IMHO the extension of a settlement is ground truth and can be surveyed or gotten from aerial imagery. The legal boundary traffic-wise isn't a boundary actually, rather it is a lot of points (city limit signs) that locally define the boundary for that piece of road. As this is not needed for anything but traffic rules it would make more sense to map it to where it belongs (the individual roads). At least around here there is no such thing as a perimeter for inside / outside the settlement under traffic aspects, there are only points (and those are sometimes moved inward or outward the actual built-up area, just as it seems appropriate under traffic aspects). Cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
On Tue, May 27, 2014 at 3:37 PM, Fernando Trebien wrote: > I like Nelson's idea of using a new value for "boundary" to represent > this, mainly because the perimeter is not "ground truth" but an > invisible "legal definition" that roughly matches the urbanized area. > I was wondering if this concept exists elsewhere so that we can even > propose such value in a way that's reusable worldwide. That's the point. Is it "legal" or just the sum of all urbanized "landuse" 's (residential, industrial, retail). Does it include backyards, garden, orchard, etc ? The limit is often clear on the road (first/last building + road sign) but fuzzy on aerial imagery if you want to draw the area. And if all landuses are already mapped, do you add a new polygon reusing existing nodes or do you create a multipolygon relation (splitting the existing landuse) or you just collect the sum of existing landuses ? Pieren ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
On Tue, May 27, 2014 at 11:27 AM, Pieren wrote: > That's the point. Is it "legal" or just the sum of all urbanized > "landuse" 's (residential, industrial, retail). Does it include > backyards, garden, orchard, etc ? The limit is often clear on the road > (first/last building + road sign) but fuzzy on aerial imagery if you > want to draw the area. And if all landuses are already mapped, do you > add a new polygon reusing existing nodes or do you create a > multipolygon relation (splitting the existing landuse) or you just > collect the sum of existing landuses ? The urban limit/boundary is legal (defined by law) here in Brazil. It may englobe areas that still lack a specific use or are not yet populated. It's not only a simple sum of the landuses. It determines, for example, the area that is taxed by the municipality (the urban perimeter/area) or by the federation (the rural area). Example: http://here.com/-22.3837691,-47.3933969,12,0,0,normal.day It's the greyish areas englobing the cities. About mapping it, I see it exactly as mapping administrative boundaries: reuse nodes/ways as needed (or as possible, or as wanted). ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
Yes, in Brazil that is a legal definition. That's why it will often not correspond to areas marked using landuse=*. You may find farms on the urban side of those limits (whose residents pay taxes under the urban tax system), and dense urban settlements on the outside (whose residents pay taxes under the rural tax system). This often happens when the legal definition has not been updated to reflect reality. As I said initially, in Brazil it also determines what environmental policy is followed by authorities. The "urban perimeter" is a "major factor" used by transit authorities to establish maximum speeds, but not the only criteria for that. So yes, you do find a few high speed highways on the urban side and a few low speed areas on the rural side, but these are the exceptions (usually where a new urban cluster is forming within a municipality but is still dependent on the municipality's local government). Several similar (not equal!) concepts I've found, but with different implications: - urban growth boundary: https://en.wikipedia.org/wiki/Urban_growth_boundary - urban (UK)/urbanized (US) area: https://en.wikipedia.org/wiki/Urbanized_Area#United_Kingdom Would I reuse the existing nodes or share relation members with landuse=residential/*? Only if they're sufficiently close/similar (as I would with any polygon/multipolygon out there). But they're certainly not the same thing. If all landuses are already mapped, in a country with no such similar legal definition, the "perimeter" could probably share nodes/ways along the outermost border of individual landuse=* clusters. I think it would not be a collection of such areas, though it could be and then the user would be required to merge all areas down (and possibly fill in holes) to obtain a similar result. (In fact, I think this is a more generic concept than that of the legal definition in Brazil; if this already existed in OSM, we would probably adapt our definition to it without trouble.) On Tue, May 27, 2014 at 11:27 AM, Pieren wrote: > On Tue, May 27, 2014 at 3:37 PM, Fernando Trebien > wrote: >> I like Nelson's idea of using a new value for "boundary" to represent >> this, mainly because the perimeter is not "ground truth" but an >> invisible "legal definition" that roughly matches the urbanized area. >> I was wondering if this concept exists elsewhere so that we can even >> propose such value in a way that's reusable worldwide. > > That's the point. Is it "legal" or just the sum of all urbanized > "landuse" 's (residential, industrial, retail). Does it include > backyards, garden, orchard, etc ? The limit is often clear on the road > (first/last building + road sign) but fuzzy on aerial imagery if you > want to draw the area. And if all landuses are already mapped, do you > add a new polygon reusing existing nodes or do you create a > multipolygon relation (splitting the existing landuse) or you just > collect the sum of existing landuses ? > > Pieren > > ___ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging -- Fernando Trebien +55 (51) 9962-5409 "Nullius in verba." ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
2014-05-27 17:44 GMT+02:00 Nelson A. de Oliveira : > The urban limit/boundary is legal (defined by law) here in Brazil. It > may englobe areas that still lack a specific use or are not yet > populated. > It's not only a simple sum of the landuses. > It determines, for example, the area that is taxed by the municipality > (the urban perimeter/area) or by the federation (the rural area). > I see, for this you'd most probably need a new boundary type (if it isn't the same as your administrative boundaries). cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] Urban perimeter
2014-05-27 17:53 GMT+02:00 Fernando Trebien : > The "urban perimeter" is a "major factor" used by transit authorities > to establish maximum speeds, but not the only criteria for that. So > yes, you do find a few high speed highways on the urban side and a few > low speed areas on the rural side, but these are the exceptions > basically you won't be able to use it for maxspeed then, maybe to check for improbable maxspeeds to re-survey, but not to add explicit maxspeeds to the db. cheers, Martin ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
[Tagging] editing polygons in JOSM
I don't know if the tagging listserv is the appropriate forum for this questions, but I can't find a better one. I want to try to complete several polygon editing operations using JOSM. Anybody know if this is possible or how to accomplish these tasks in JOSM or any other free editor? 1. Clip a polygon using another polygon 2. Cut a polygon using a line I already know how to create a hole in a polygon using a polygon and relate them, thus creating a multi-polygon. Thanks! Tom G. ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] editing polygons in JOSM
Hi Tom Cutting by a line is easy: - add a way with nodes for start and end of the line where it cut's the polygon first and last. - add nodes where that new way intersects the old polygon - split the new way at these nodes - split the old polygon at these nodes - delete the parts of the old polygon that is outside the new one - combine polygon and some of the new ways (parts of the one you drawed initially) where that should be done If that creates holes, combine the resulting parts as a multipolygon if necessary. Clipping by a new polygon is basically the same - but draw that new polygon first instead of the line, then proceed as described above. As far as I know there is no automatic way to do one of these. regards Peter Am 27.05.2014 20:23, schrieb Tom Gertin: > I don't know if the tagging listserv is the appropriate forum for this > questions, but I can't find a better one. > > I want to try to complete several polygon editing operations using JOSM. > Anybody know if this is possible or how to accomplish these tasks in JOSM > or any other free editor? > > 1. Clip a polygon using another polygon > 2. Cut a polygon using a line > > I already know how to create a hole in a polygon using a polygon and relate > them, thus creating a multi-polygon. > > Thanks! > > Tom G. > > > > ___ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging > ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] editing polygons in JOSM
On Tuesday 27 May 2014, Peter Wendorff wrote: > > Cutting by a line is easy: > - add a way with nodes for start and end of the line where it cut's > the polygon first and last. > - add nodes where that new way intersects the old polygon > - split the new way at these nodes > - split the old polygon at these nodes > - delete the parts of the old polygon that is outside the new one > - combine polygon and some of the new ways (parts of the one you > drawed initially) where that should be done I would not really call that easy. JOSM could really use some basic boolean operation on polygons. If you have a large multipolygon with like a hundred ways in it you want to cut in two for example this is quite cumbersome and error prone at the moment. -- Christoph Hormann http://www.imagico.de/ ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] editing polygons in JOSM
Am 27.05.2014 21:12, schrieb Peter Wendorff: Am 27.05.2014 20:23, schrieb Tom Gertin: 1. Clip a polygon using another polygon 2. Cut a polygon using a line Cutting by a line is easy: [...] Clipping by a new polygon is basically the same - but draw that new polygon first instead of the line, then proceed as described above. As far as I know there is no automatic way to do one of these. I would recommend the plug-in "utilsplugin2". This will give you new tools, e.g.: - Add nodes at intersections - Split object This will automate some, but not all of the neccesary steps. Georg ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
Re: [Tagging] editing polygons in JOSM
Since you were also looking for more appropriate places to ask those questions: The help-website: http://help.openstreetmap.org or the editors forum : http://forum.openstreetmap.org/viewforum.php?id=54 regards On Tue, May 27, 2014 at 11:11 PM, Georg Feddern wrote: > Am 27.05.2014 21:12, schrieb Peter Wendorff: > >> Am 27.05.2014 20:23, schrieb Tom Gertin: >> >> 1. Clip a polygon using another polygon >>> 2. Cut a polygon using a line >>> >> Cutting by a line is easy: >> [...] >> >> Clipping by a new polygon is basically the same - but draw that new >> polygon first instead of the line, then proceed as described above. >> >> As far as I know there is no automatic way to do one of these. >> > > I would recommend the plug-in "utilsplugin2". > This will give you new tools, e.g.: > - Add nodes at intersections > - Split object > > This will automate some, but not all of the neccesary steps. > > Georg > > > ___ > Tagging mailing list > Tagging@openstreetmap.org > https://lists.openstreetmap.org/listinfo/tagging > ___ Tagging mailing list Tagging@openstreetmap.org https://lists.openstreetmap.org/listinfo/tagging
