8 ms·

OpenStreetMap node density map 2014

139 points by lelf 12y ago

Vik1ng 12y ago
Blogpost from the guy who made it: http://www.openstreetmap.org/user/tyr_asd/diary/22363 http://www.openstreetmap.org/user/tyr_asd/diary/22363
phaer 12y ago
The site runs over https but loads leaflet over http, so that it get's blocked at least by recent versions of Firefox, Chrom[e/ium] and Internet Explorer. https://developer.mozilla.org/en-US/docs/Security/MixedContent/How_to_fix_website_with_mixed_content https://developer.mozilla.org/en-US/docs/Security/MixedConte...
- finnn 12y ago
  Actually the link was an http link. You likely have HTTPS Everywhere that changed that.
  - stereo 12y ago
    It’s still nice, if all the content is available over both http and http, to use protocol-relative URLs, i.e. without http or https before the //: part. It looks like the author has read your comment, and updated his source code to say <script src="//cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.js”> for leaflet. http://www.paulirish.com/2010/the-protocol-relative-url/ http://www.paulirish.com/2010/the-protocol-relative-url/ describes how protocol-relative URLs work.
  - phaer 12y ago
    You are right, I missed that. But you should have protocol relative urls on servers which run https.
    - finnn 12y ago
      It's not my site. I'd force everyone to https if it was
lucb1e 12y ago
Looks like The Netherlands is one of the most dense countries in the world. I wonder why that is, we (speaking as a Dutch person) hardly seem to use OSM while in Germany it's very popular. One explanation is the recent addition of the government's address and building data, which gives us close to perfect outlines for every building in the country plus an extra node per address. Or we just have a high number of people per square kilometer regardless of the recent (now almost finished) data import. Edit: Looks like it's simply our density in general and not this import; last year the Netherlands also stood out while we hadn't even imported 10% yet. From last year: http://www.openstreetmap.org/user/tyr_asd/diary/19549 http://www.openstreetmap.org/user/tyr_asd/diary/19549
- lelf 12y ago
  https://wiki.openstreetmap.org/wiki/AND_Data https://wiki.openstreetmap.org/wiki/AND_Data ?
  - lucb1e 12y ago
    That and 3dshapes[1] helped a lot of course, but since we started importing BAG data in March the map size (looking at the OsmAnd map file) roughly doubled. Thought that might also influence this density map a lot but it doesn't seem so. [1] https://wiki.openstreetmap.org/wiki/3dShapes https://wiki.openstreetmap.org/wiki/3dShapes
- maxerickson 12y ago
  The buildings have a huge impact. Look at New York, Chicago or San Francisco. They also had building imports and they shine quite brightly.
- robin2 12y ago
  My guess is that this might be cycling related; that an area where there's likely to be public-spirited cyclists with GPS devices is well placed to get good OSM coverage. In support of my theory, I point to Cambridge being a little bit of a hotspot in the southeast of England. (Not so much as Clacton though ... hmmm ... maybe the theory needs some work.)
deleted 12y ago
[deleted]
runlevel1 12y ago
Interesting how brightly Bakersfield and Fresno glow. I wonder if it's because the streets are so gridded and therefore not as prone to aliasing.
- maxerickson 12y ago
  Each pixel represents quite a lot of area so aliasing probably isn't coming into it. Bakersfield has a bunch of buildings (which lines up with the theory in my other post in this thread). It looks like imported land parcels make up a lot of the data in the Fresno blob: http://www.openstreetmap.org/#map=16/36.7805/-119.9009&layers=D http://www.openstreetmap.org/#map=16/36.7805/-119.9009&layer... (Probably a good idea to turn off the data layer there before zooming out)
- Vik1ng 12y ago
  > Fresno Data Import http://wiki.openstreetmap.org/wiki/Talk:Fresno_County,_California http://wiki.openstreetmap.org/wiki/Talk:Fresno_County,_Calif...
- dublinben 12y ago
  You can also see the border of Massachusetts perfectly clearly, likely due to the import of MassGIS data. Surrounding states are all much lower density, until you hit Manhattan.
3rd3 12y ago
It would be interesting to see this map adjusted to population density.
- lucb1e 12y ago
  Well count the building tags and you got a rough population estimate for any area.
  - 3rd3 12y ago
    I tried to overlay this map with a map showing population density from Google Images and then normalize it with a division filter. I couldn’t find an map with a matching projection however. :(
    - throwaway_yy2Di 12y ago
      Check back here in a bit, I'll try to make one. I already have the OSM database and some related glue code, it shouldn't be too far out the way.
  - sashazykov 12y ago
    It won't work, since the average number of people living in one building varies with the country. I guess it should be around 10 people per building in USA and 100 people per building in Russia, for example.
- throwaway_yy2Di 12y ago
  Here you go! https://imgur.com/a/b6BjV https://imgur.com/a/b6BjV edit: Um, it seems Imgur does lossy compression now? Sorry about that -- here's a sample of the original (2.5 arcminutes, limited by the census data) https://i.imgur.com/hBNEGNT.png https://i.imgur.com/hBNEGNT.png
malandrew 12y ago
I found the map of greenland fascinating, since there is pitch black internally. Everything is along the coast. At the lowest zoom level what are geometric lines that criss cross Greenland and the curvilinear lines and rings off the coasts?
- maxerickson 12y ago
  Do you mean like this one: http://www.openstreetmap.org/way/28421901#map=9/59.1125/-5.9903 http://www.openstreetmap.org/way/28421901#map=9/59.1125/-5.9... That's just territorial waters. The lines across Greenland are administrative borders: http://www.openstreetmap.org/way/238745790#map=4/71.15/-44.17 http://www.openstreetmap.org/way/238745790#map=4/71.15/-44.1... I guess there is so little mapped there that they can stand out.
- analog31 12y ago
  Another interesting note: I would have expected North Korea to be dark, but it's brighter than neighboring China.
  - guard-of-terra 12y ago
    And South Korea is not nearly as bright as its population and wealth suggests.
BoppreH 12y ago
I'm sorry, but I don't see any much use in this visualization. It's pretty, but gives almost no information at the global level, for two reasons: 1) It's not adjusted for population ( http://xkcd.com/1138/ http://xkcd.com/1138/ ). They can normalize the data to fix this. 2) The map is ludicrously distorted because of the Mercator projection. Greenland looks bigger than the entire South America, when it should be an eighth of the size. This directly affects the perceived density in each area. Suggestion: if you are using an interactive geographical visualization, why not display a globe? However, it does look stunning.
- BoppreH 12y ago
  By the way, West Wing had an excellent piece where they explain the need for accurate map projections: https://www.youtube.com/watch?v=n8zBC2dvERM https://www.youtube.com/watch?v=n8zBC2dvERM
- maxerickson 12y ago
  There is no claim that the density means anything, so there isn't any need to adjust it for population. I imagine the title "OpenStreetMap node density map 2014" was somewhat carefully chosen, and it manages to say what is shown. If you read the link that Vik1ng posted, the author seems to be fairly clear that they were just making a pretty picture (and quietly points out the problems with the projection).
  - BoppreH 12y ago
    Density here is number of nodes by area, and if you distort the area it stops being density. It's like comparing the weight of different objects on different planets. "My shoe on Earth weights twice as much as my sandal on Saturn" isn't very useful. And thanks for mentioning the link, but I don't see where they say it was made for a pretty picture.
    - maxerickson 12y ago
      Yes, I said "seems to be" to suggest that it was my impression of the page, rather than a quote from it or whatever. Part of that impression is that you can't really zoom in far enough to do anything super useful with it, so it's probably just to look at.
twic 12y ago
What are the rectangular features in northwestern Canada?
- moron4hire 12y ago
  Perhaps satellite or aerial photography.
- maxerickson 12y ago
  On one side "CanVec" data has been imported and on the other it has not. If you zoom in from here you see all the small streams that are showing up in the visualization: http://www.openstreetmap.org/way/157650655 http://www.openstreetmap.org/way/157650655 That doesn't explain the differences on the imported side, but I guess that could just be more imports vs less imports.
ajtaylor 12y ago
The whole of Massachusetts is brighter than the surrounding states, and grows brighter the closer you get to Boston. I wonder where all that data came from. Was it a corporate or state data donation?
- maxerickson 12y ago
  For the state, it's "MassGIS" data. Many of the points are from road center lines that are a lot denser than is typical in OSM, but there is also land use/classification data (like wetlands or whatever).
  - ajtaylor 12y ago
    Thanks for the information.

139 points by lelf 12y ago

Blogpost from the guy who made it: http://www.openstreetmap.org/user/tyr_asd/diary/22363 http://www.openstreetmap.org/user/tyr_asd/diary/22363

phaer 12y ago

The site runs over https but loads leaflet over http, so that it get's blocked at least by recent versions of Firefox, Chrom[e/ium] and Internet Explorer. https://developer.mozilla.org/en-US/docs/Security/MixedContent/How_to_fix_website_with_mixed_content https://developer.mozilla.org/en-US/docs/Security/MixedConte...

finnn 12y ago
Actually the link was an http link. You likely have HTTPS Everywhere that changed that.
- stereo 12y ago
  It’s still nice, if all the content is available over both http and http, to use protocol-relative URLs, i.e. without http or https before the //: part. It looks like the author has read your comment, and updated his source code to say <script src="//cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.3/leaflet.js”> for leaflet. http://www.paulirish.com/2010/the-protocol-relative-url/ http://www.paulirish.com/2010/the-protocol-relative-url/ describes how protocol-relative URLs work.
- phaer 12y ago
  You are right, I missed that. But you should have protocol relative urls on servers which run https.
  - finnn 12y ago
    It's not my site. I'd force everyone to https if it was

lucb1e 12y ago

Looks like The Netherlands is one of the most dense countries in the world. I wonder why that is, we (speaking as a Dutch person) hardly seem to use OSM while in Germany it's very popular. One explanation is the recent addition of the government's address and building data, which gives us close to perfect outlines for every building in the country plus an extra node per address. Or we just have a high number of people per square kilometer regardless of the recent (now almost finished) data import. Edit: Looks like it's simply our density in general and not this import; last year the Netherlands also stood out while we hadn't even imported 10% yet. From last year: http://www.openstreetmap.org/user/tyr_asd/diary/19549 http://www.openstreetmap.org/user/tyr_asd/diary/19549

lelf 12y ago
https://wiki.openstreetmap.org/wiki/AND_Data https://wiki.openstreetmap.org/wiki/AND_Data ?
- lucb1e 12y ago
  That and 3dshapes[1] helped a lot of course, but since we started importing BAG data in March the map size (looking at the OsmAnd map file) roughly doubled. Thought that might also influence this density map a lot but it doesn't seem so. [1] https://wiki.openstreetmap.org/wiki/3dShapes https://wiki.openstreetmap.org/wiki/3dShapes
maxerickson 12y ago
The buildings have a huge impact. Look at New York, Chicago or San Francisco. They also had building imports and they shine quite brightly.
robin2 12y ago
My guess is that this might be cycling related; that an area where there's likely to be public-spirited cyclists with GPS devices is well placed to get good OSM coverage. In support of my theory, I point to Cambridge being a little bit of a hotspot in the southeast of England. (Not so much as Clacton though ... hmmm ... maybe the theory needs some work.)

deleted 12y ago

[deleted]

runlevel1 12y ago

Interesting how brightly Bakersfield and Fresno glow. I wonder if it's because the streets are so gridded and therefore not as prone to aliasing.

maxerickson 12y ago
Each pixel represents quite a lot of area so aliasing probably isn't coming into it. Bakersfield has a bunch of buildings (which lines up with the theory in my other post in this thread). It looks like imported land parcels make up a lot of the data in the Fresno blob: http://www.openstreetmap.org/#map=16/36.7805/-119.9009&layers=D http://www.openstreetmap.org/#map=16/36.7805/-119.9009&layer... (Probably a good idea to turn off the data layer there before zooming out)
Vik1ng 12y ago
> Fresno Data Import http://wiki.openstreetmap.org/wiki/Talk:Fresno_County,_California http://wiki.openstreetmap.org/wiki/Talk:Fresno_County,_Calif...
dublinben 12y ago
You can also see the border of Massachusetts perfectly clearly, likely due to the import of MassGIS data. Surrounding states are all much lower density, until you hit Manhattan.

3rd3 12y ago

It would be interesting to see this map adjusted to population density.

lucb1e 12y ago
Well count the building tags and you got a rough population estimate for any area.
- 3rd3 12y ago
  I tried to overlay this map with a map showing population density from Google Images and then normalize it with a division filter. I couldn’t find an map with a matching projection however. :(
  - throwaway_yy2Di 12y ago
    Check back here in a bit, I'll try to make one. I already have the OSM database and some related glue code, it shouldn't be too far out the way.
- sashazykov 12y ago
  It won't work, since the average number of people living in one building varies with the country. I guess it should be around 10 people per building in USA and 100 people per building in Russia, for example.
throwaway_yy2Di 12y ago
Here you go! https://imgur.com/a/b6BjV https://imgur.com/a/b6BjV edit: Um, it seems Imgur does lossy compression now? Sorry about that -- here's a sample of the original (2.5 arcminutes, limited by the census data) https://i.imgur.com/hBNEGNT.png https://i.imgur.com/hBNEGNT.png

malandrew 12y ago

I found the map of greenland fascinating, since there is pitch black internally. Everything is along the coast. At the lowest zoom level what are geometric lines that criss cross Greenland and the curvilinear lines and rings off the coasts?

maxerickson 12y ago
Do you mean like this one: http://www.openstreetmap.org/way/28421901#map=9/59.1125/-5.9903 http://www.openstreetmap.org/way/28421901#map=9/59.1125/-5.9... That's just territorial waters. The lines across Greenland are administrative borders: http://www.openstreetmap.org/way/238745790#map=4/71.15/-44.17 http://www.openstreetmap.org/way/238745790#map=4/71.15/-44.1... I guess there is so little mapped there that they can stand out.
analog31 12y ago
Another interesting note: I would have expected North Korea to be dark, but it's brighter than neighboring China.
- guard-of-terra 12y ago
  And South Korea is not nearly as bright as its population and wealth suggests.

BoppreH 12y ago

I'm sorry, but I don't see any much use in this visualization. It's pretty, but gives almost no information at the global level, for two reasons: 1) It's not adjusted for population ( http://xkcd.com/1138/ http://xkcd.com/1138/ ). They can normalize the data to fix this. 2) The map is ludicrously distorted because of the Mercator projection. Greenland looks bigger than the entire South America, when it should be an eighth of the size. This directly affects the perceived density in each area. Suggestion: if you are using an interactive geographical visualization, why not display a globe? However, it does look stunning.

BoppreH 12y ago
By the way, West Wing had an excellent piece where they explain the need for accurate map projections: https://www.youtube.com/watch?v=n8zBC2dvERM https://www.youtube.com/watch?v=n8zBC2dvERM
maxerickson 12y ago
There is no claim that the density means anything, so there isn't any need to adjust it for population. I imagine the title "OpenStreetMap node density map 2014" was somewhat carefully chosen, and it manages to say what is shown. If you read the link that Vik1ng posted, the author seems to be fairly clear that they were just making a pretty picture (and quietly points out the problems with the projection).
- BoppreH 12y ago
  Density here is number of nodes by area, and if you distort the area it stops being density. It's like comparing the weight of different objects on different planets. "My shoe on Earth weights twice as much as my sandal on Saturn" isn't very useful. And thanks for mentioning the link, but I don't see where they say it was made for a pretty picture.
  - maxerickson 12y ago
    Yes, I said "seems to be" to suggest that it was my impression of the page, rather than a quote from it or whatever. Part of that impression is that you can't really zoom in far enough to do anything super useful with it, so it's probably just to look at.

twic 12y ago

What are the rectangular features in northwestern Canada?

moron4hire 12y ago
Perhaps satellite or aerial photography.
maxerickson 12y ago
On one side "CanVec" data has been imported and on the other it has not. If you zoom in from here you see all the small streams that are showing up in the visualization: http://www.openstreetmap.org/way/157650655 http://www.openstreetmap.org/way/157650655 That doesn't explain the differences on the imported side, but I guess that could just be more imports vs less imports.

ajtaylor 12y ago

The whole of Massachusetts is brighter than the surrounding states, and grows brighter the closer you get to Boston. I wonder where all that data came from. Was it a corporate or state data donation?

maxerickson 12y ago
For the state, it's "MassGIS" data. Many of the points are from road center lines that are a lot denser than is typical in OSM, but there is also land use/classification data (like wetlands or whatever).
- ajtaylor 12y ago
  Thanks for the information.