Re: [OSM-talk] Most complete cities and administrative divisions database
SomeoneElse wrote: How many of them are vaguely close to the correct location though? I tried a few local (UK) village names. About half weren't found, and none of the others were close enough to their actual location to be useful. Not to forget double entries in geonames. I see quite some of them using geonames WMS. malenki ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Most complete cities and administrative divisions database
I was asking about its administrative boundary. So, after reading http://wiki.openstreetmap.org/wiki/Key:place, what I understand is that : - Cities are marked as nodes - Sometimes, there are additional ways (boundary=administrative) to delimit the administrative boundary - As a bonus, there can be relations that link the city node to its boundary. Yes So now, let's go with other administrative divisions : Now, let's say I want to add an entry for Orange County. How should I do it ? Should it just appear as a boundary=administrative, or should there be some kind of node node and a relation ? Well, stage 1 should be to check if it exists or not - which it does I think: http://open.mapquestapi.com/nominatim/v1/search.php?q=Orange+Countypolygon=1 But, ignoring that if you have the data creating it as a relation is normally best. The nodes are mostly a legacy where an area initially didn't have a boundary=administrative relation and it was added afterwards. For some reason people seem reluctant to delete the node - probably because the node allows more accurate label placement (tagging for renderer - naughty!) -- Brian ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Most complete cities and administrative divisions database
2011/1/26 Sami Dalouche sko...@free.fr: he geonames project (http://www.geonames.org/) provides over 7 million POI, and 2 million of them are cities. 2 million can IMHO only refer to all settlements, not just to cities. There is around 7 billion people living on earth, ~ half of them in cities. If you divide 3,5 billion people by 2 million, you get an average of 1750 people per city. Not quite much ;-) (or they have lots of multiple entries). So, more specifically, here are my questions : 1/ how many cities are present in OSM ? this is easy to answer: http://taginfo.openstreetmap.de/keys/place#values 492 155 village 397 919 hamlet 57 083 town 44 450 suburb 18 942 city 2/ how many of these cities are also associated to polygons that delimit them ? are you asking about the city or about it's administrative boundary? http://taginfo.openstreetmap.de/keys/boundary#values 3/ Are countries and administrative divisions also explicited in OSM ? (e.g. USA, California, Orange county, ..) you can do this with relations 4/ Are there polygons for these administrative divisions and countries ? you can get them from the relations (if the relations are there and are clean). Have a look at type=boundary and type=multipolygon Cheers, Martin ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Most complete cities and administrative divisions database
Mâ¡rtin Koppenhoefer wrote: 2/ how many of these cities are also associated to polygons that delimit them ? are you asking about the city or about it's administrative boundary? http://taginfo.openstreetmap.de/keys/boundary#values And: http://taginfo.openstreetmap.de/keys/place?filter=ways#values And maybe: http://taginfo.openstreetmap.de/keys/place?filter=relations#values Greets, Floris ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Most complete cities and administrative divisions database
On 26/01/2011 15:53, Sami Dalouche wrote: For instance, the geonames project (http://www.geonames.org/) provides over 7 million POI, and 2 million of them are cities. How many of them are vaguely close to the correct location though? I tried a few local (UK) village names. About half weren't found, and none of the others were close enough to their actual location to be useful. So I'd switch _from_ geonames for that reason alone. Cheers, Andy ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Most complete cities and administrative divisions database
On 11-01-26 12:13 PM, M∡rtin Koppenhoefer wrote: 2011/1/26 Sami Dalouchesko...@free.fr: he geonames project (http://www.geonames.org/) provides over 7 million POI, and 2 million of them are cities. 2 million can IMHO only refer to all settlements, not just to cities. There is around 7 billion people living on earth, ~ half of them in cities. If you divide 3,5 billion people by 2 million, you get an average of 1750 people per city. Not quite much ;-) (or they have lots of multiple entries). Yes, actually I was using the word 'city' where I should have been using 'place' or 'settlement'. The 2 million count includes all populated places in Geonames. (and includes junk such as junctions that are tagged as populated places). So, more specifically, here are my questions : 1/ how many cities are present in OSM ? this is easy to answer: http://taginfo.openstreetmap.de/keys/place#values 492 155 village 397 919 hamlet 57 083 town 44 450 suburb 18 942 city Wao, great tool ! So, I guess that ~1 million populated places makes OSM complete-enough for locating most important populated places. BTW, most places in geonames also have an associated timezone. Is there any freely available database of timezones with the latitudes/longitudes bounds ? This could serve as a replacement for geonames' timezone field. 2/ how many of these cities are also associated to polygons that delimit them ? are you asking about the city or about it's administrative boundary? http://taginfo.openstreetmap.de/keys/boundary#values I was asking about its administrative boundary. So, after reading http://wiki.openstreetmap.org/wiki/Key:place, what I understand is that : - Cities are marked as nodes - Sometimes, there are additional ways (boundary=administrative) to delimit the administrative boundary - As a bonus, there can be relations that link the city node to its boundary. Am I right ? So now, let's go with other administrative divisions : Now, let's say I want to add an entry for Orange County. How should I do it ? Should it just appear as a boundary=administrative, or should there be some kind of node node and a relation ? 3/ Are countries and administrative divisions also explicited in OSM ? (e.g. USA, California, Orange county, ..) you can do this with relations 4/ Are there polygons for these administrative divisions and countries ? you can get them from the relations (if the relations are there and are clean). Have a look at type=boundary and type=multipolygon Cheers, Martin Thanks for your help ! Sami Dalouche ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
Re: [OSM-talk] Most complete cities and administrative divisions database
2011/1/26 Sami Dalouche sko...@free.fr: are you asking about the city or about it's administrative boundary? http://taginfo.openstreetmap.de/keys/boundary#values I was asking about its administrative boundary. So, after reading http://wiki.openstreetmap.org/wiki/Key:place, what I understand is that : - Cities are marked as nodes well, they can also be marked as polygons (delimiting the actual built-up area, place-tag), but as our major renderer mapnik doesn't support this, there is very few places mapped like this (it would make them disappear from the rendering). - Sometimes, there are additional ways (boundary=administrative) to delimit the administrative boundary yes, usually this would be relations, because they allow to use the ways several times (for the areas each side of the way) - As a bonus, there can be relations that link the city node to its boundary. yes, might be, there should / could also be hierarchical structure / nested relations, etc. So now, let's go with other administrative divisions : Now, let's say I want to add an entry for Orange County. How should I do it ? Should it just appear as a boundary=administrative, yes, this should go into an administrative relation and get its admin_level for county ( 6 ) http://wiki.openstreetmap.org/wiki/Admin_level cheers, Martin ___ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
