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Be aware that those extracts are squares around the cities - they're not exact city border outlines. This means that you can't just use the data without concern

Be aware that those extracts are squares around the cities - they're not exact city border outlines. This means that you can't just use the data without concern for whether the things you're gathering are actually within the city or not. I haven't found a very simple way to get everything within exact city borders, yet. This is the process I've been going with so far: https://github.com/JamesChevalier/cities#cities https://github.com/JamesChevalier/cities#cities

olefoo 13y ago
That is a very useful resource; thank you. Some cities make shapefiles available for urban growth boundaries and city limits. It's worth enquiring. But be aware that some cities city limits are not simple polygons; depending on local ordinances you can see islands, internal voids and peninsulas attached with zero width stems.
- JamesChevalier 13y ago
  True! Like Houston, TX ... which looks a little like the flying spaghetti monster ... http://nominatim.openstreetmap.org/details.php?place_id=3675649666 http://nominatim.openstreetmap.org/details.php?place_id=3675... The poly files that you get from the process outlined in the readme file will include islands/voids. It's pretty cool.
rmc 13y ago
Well remember OSM is an international project, so trying to find one definition of "city" and "border of a city" is hard. Some places (like USA) seem to use "city" as a hard solid thing, other places (eg UK / ireland) don't.
- JamesChevalier 13y ago
  Yeah - OSM goes a long way in categorizing different levels of "area in which people live" based on population density. http://wiki.openstreetmap.org/wiki/Key:place http://wiki.openstreetmap.org/wiki/Key:place
  - rmc 13y ago
    Except that the place tag isn't always based on population size. In some places, (e.g. UK), a common cultural definition of a "city" is archaic, and depends if the place has a Cathedral and/or charter from the monarch. I give you the "city" of St. David's: http://www.openstreetmap.org/browse/node/3216768 http://www.openstreetmap.org/browse/node/3216768 It's in Wales, UK, and is tagged as "place=city". It's a small town of ~2,000 people. It has a charter from the monarch, and a cathedral. The "note" tag in OSM says: "the "city" is on paper, what's on the ground is a small town". Humanity is complicated. :)
    - JamesChevalier 13y ago
      heh, true! I've been playing with place names & http://overpass-turbo.eu/ http://overpass-turbo.eu/ ... I seem to be getting the best results with "city|hamlet|metropolis|town|village", although some states like Alaska & Hawaii still don't return much with this scope. In Alaska, a lot of places are labeled as County. In Hawaii, a lot of places are labeled as Other.
    - huxley 13y ago
      UK isn't the only place with weird "cities". Greenhorn, Oregon is designated as a city but has a 2010 census population of zero. Though now unicorporated, Tenny, Minnesota, was a city and had a peak population of 180 people in 1910 but now is down to 5 (2010 census).

olefoo 13y ago

That is a very useful resource; thank you. Some cities make shapefiles available for urban growth boundaries and city limits. It's worth enquiring. But be aware that some cities city limits are not simple polygons; depending on local ordinances you can see islands, internal voids and peninsulas attached with zero width stems.

JamesChevalier 13y ago
True! Like Houston, TX ... which looks a little like the flying spaghetti monster ... http://nominatim.openstreetmap.org/details.php?place_id=3675649666 http://nominatim.openstreetmap.org/details.php?place_id=3675... The poly files that you get from the process outlined in the readme file will include islands/voids. It's pretty cool.

rmc 13y ago

Well remember OSM is an international project, so trying to find one definition of "city" and "border of a city" is hard. Some places (like USA) seem to use "city" as a hard solid thing, other places (eg UK / ireland) don't.

JamesChevalier 13y ago
Yeah - OSM goes a long way in categorizing different levels of "area in which people live" based on population density. http://wiki.openstreetmap.org/wiki/Key:place http://wiki.openstreetmap.org/wiki/Key:place
- rmc 13y ago
  Except that the place tag isn't always based on population size. In some places, (e.g. UK), a common cultural definition of a "city" is archaic, and depends if the place has a Cathedral and/or charter from the monarch. I give you the "city" of St. David's: http://www.openstreetmap.org/browse/node/3216768 http://www.openstreetmap.org/browse/node/3216768 It's in Wales, UK, and is tagged as "place=city". It's a small town of ~2,000 people. It has a charter from the monarch, and a cathedral. The "note" tag in OSM says: "the "city" is on paper, what's on the ground is a small town". Humanity is complicated. :)
  - JamesChevalier 13y ago
    heh, true! I've been playing with place names & http://overpass-turbo.eu/ http://overpass-turbo.eu/ ... I seem to be getting the best results with "city|hamlet|metropolis|town|village", although some states like Alaska & Hawaii still don't return much with this scope. In Alaska, a lot of places are labeled as County. In Hawaii, a lot of places are labeled as Other.
  - huxley 13y ago
    UK isn't the only place with weird "cities". Greenhorn, Oregon is designated as a city but has a 2010 census population of zero. Though now unicorporated, Tenny, Minnesota, was a city and had a peak population of 180 people in 1910 but now is down to 5 (2010 census).