[OSM-dev] Graphical representation of quad-tile road populations in Europe

Kenn Sebesta kenn at wifi-bourgogne.com
Fri Apr 10 15:00:17 BST 2009


www.eissq.com/osm/qt/

This is a spinoff from a need I had for a research project. I had to
generate a quad-tree structure in order to geo-localize my sensor as
quickly as possible, with the least amount of programming (target
platform is a microcontroller). These images are just a natural
side-effect of the program.

While limited to Europe only, I still find them interesting because
you can see in the blink of an eye how different countries are better
or worse represented in OSM. Compare, for instance, the two biggest
countries in Europe: France and Germany.

Each block represents the largest quad-tile containing 20 ways or
less. The color represents how many ways there are in a block, with
red being the most and blue the least (the "jet" colormap).

Lastly, it's normal that some countries look squashed. This is because
I haven't corrected for the converging lines of longitude at these
higher elevations. It's also perfectly normal that the images are not
to scale. I scaled them down to fit, so relative sizes are not equal.
If you view the full size image, you'll see there is much more detail.

The code I used for this is Matlab, and I will happily link to it if
anyone is interested. It would be very easy to do this from C.
Furthermore, it would be faster if it were done from a database,
instead of the planet dumps. It would be interesting to generate these
images for other countries outside of Europe, or even perhaps on a
routine basis in order to track the evolution of OSM. Perhaps it can
even be used as motivation for countries that are falling behind.

Feedback welcome.

Cheers,
Kenn Sebesta




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