OpenStreetMap node density map 2014

http://tyrasd.github.io/osm-node-density/#2/32.2/5.6

by lelf • 12 years ago

139 51 12 years ago

tyrasd.github.io

Vik1ng4• 12 years ago

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

phaer2• 12 years 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/MixedConte...

finnn2• 12 years ago

Actually the link was an http link. You likely have HTTPS Everywhere that changed that.

stereo• 12 years 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/ describes how protocol-relative URLs work.

phaer2• 12 years ago

You are right, I missed that. But you should have protocol relative urls on servers which run https.

lucb1e3• 12 years 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

lelf• 12 years ago

https://wiki.openstreetmap.org/wiki/AND_Data ?

lucb1e3• 12 years 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

maxerickson9• 12 years 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• 12 years 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.)

Brakenshire• 12 years ago

Isn't Cambridge where OpenStreetMap started? That's a bit of a confounding factor!

runlevel1• 12 years 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.

maxerickson9• 12 years 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&layer...

(Probably a good idea to turn off the data layer there before zooming out)

Vik1ng4• 12 years ago

Fresno

Data Import

http://wiki.openstreetmap.org/wiki/Talk:Fresno_County,_Calif...

dublinben• 12 years 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.

3rd32• 12 years ago

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

lucb1e3• 12 years ago

Well count the building tags and you got a rough population estimate for any area.

3rd32• 12 years 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. :(

sashazykov• 12 years 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_yy2Di2• 12 years ago

Here you go!

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

malandrew• 12 years 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?

maxerickson9• 12 years ago

Do you mean like this one:

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/-44.1...

I guess there is so little mapped there that they can stand out.

analog31• 12 years ago

Another interesting note: I would have expected North Korea to be dark, but it's brighter than neighboring China.

guard-of-terra• 12 years ago

And South Korea is not nearly as bright as its population and wealth suggests.

BoppreH7• 12 years 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/ ). 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.

BoppreH7• 12 years 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

maxerickson9• 12 years 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).

BoppreH7• 12 years 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.

Vik1ng4• 12 years ago

@1 I think the main goal is simply to display OpenStreetMap node density. Nothing more and nothing less. For mappers it's kinda interesting. He did't want to make a map where the most active mappers are.

BoppreH7• 12 years ago

But if it's the same as a population map, what good is it?

If I had asked you about nodes density before you saw this picture, your guess would probably use the population density. If your guess remains the same after seeing the picture, it didn't give you any useful information.

I think this is gorgeous, and the process of making a visualization is interesting, but I'm questioning the usefulness of the information portrayed.

laurent123456• 12 years ago

That what I thought at first but the visualization is actually useful. For instance, I have the offline OpenStreet map of Germany on my phone, which is about 1GB. In comparison, the map China is about 110MB, despite having a population 15 times bigger. The node density map does actually reflect this kind of differences. I find the difference between Brazil, Chile and Argentina also quite interesting.

twic• 12 years ago

What are the rectangular features in northwestern Canada?

moron4hire• 12 years ago

Perhaps satellite or aerial photography.

maxerickson9• 12 years 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

That doesn't explain the differences on the imported side, but I guess that could just be more imports vs less imports.

ajtaylor2• 12 years 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?

maxerickson9• 12 years 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).

ajtaylor2• 12 years ago

Thanks for the information.

OpenStreetMap node density map 2014

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