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A choropleth map about german population

24. April 2013

The german “Bundesamt für Kartographie and Geodäsie” recently published some OpenData (read, inspect), including the administrative boundaries related to the DLM 250.

As some shapefiles contain also the number of population for the administrative units, I thought it would be a good idea, to use my new JavaScript- and D3-knowledge to make a choropleth map of german population.

choropleth_germany

I useed TopoJSON to reduce file size of the corresponding JSON files. Let’s have a look at that:

  • all shapefiles: ~48,1 MB
  • all GeoJSON: ~120,4 MB
  • one TopoJSON: ~ 8,5 MB

That makes a reduction of size:

  • for shape: ~82%
  • for GeoJSON: ~93%

That is really impressive, isn’t it?

But the map is still very slow…depending on the device…as the geometries are way too detailled.

Further developments and post will follow for this…

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4 Comments
  1. Hey, have you had a look @ http://bost.ocks.org/mike/simplify/ for line Simplification?

    • Yes for sure…I’ve already played a little bit with it and I do plan to integrate it to this map!

  2. Franz Finke permalink

    Hello, I followed your link to the website of the BKG, but could not find a download for the GeoJSON for the map you are visualizing. Additionally the link to your demo is down. It would by nice if you can provide some addional information on how you obtained the data and transformed it into the TopoJSON format.

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