[OSM-talk] Visually detect missing roads

[Stephan Knauss]

I did announce this on the German list last week. As the load did not 
cause the server to catch fire I'm now announcing it to a wider audience.

I have created a map which visually diffs our data against Google Maps.
Currently it compares major highways (unclassified and higher) and water 
features.

The data is styled to show up in bright colors. If there is "matching" 
data in OSM it would hide the Google data.

So in a "perfect" area the map would be grey. Differences stay visible.

You can try it here: http://compare.osm-tools.org/

It has the possibility to directly load the visible area into the editors.

More details can be found here: http://www.osm-tools.org/compare.html

or if you're able to read German in my blog post at 
http://www.technologyblog.de/2014/08/wo-fehlen-bei-openstreetmap-noch-daten/

In well-mapped areas the differences are usually caused by OSM data not 
being tagged as a major highway. If you're looking for areas where roads 
are actually missing and can be drawn from aerials head over to Asia.

Hope this helps all people interested in arm-chair mapping to focus on 
the major missing parts of OSM-data.

If you pan the map fast you'll see the original Google data. This is 
caused by the way technical way the images are layered. When using 
Google API instead of OpenLayers it would not do this but caching of 
tiles is worse with Google. That's why I decided to use OL.

Enjoy mapping!

Stephan