Historical Coverage

From OpenStreetMap

User:Frederik Ramm operates a history service that can be used to create animate GIF images for any bounding box, showing how OSM coverage of an area developed over time.

Here's an example of Europe (the animation may only be visible after you click on the image and load the full-size version):

You can influence the style of image generated using some parameters (projection, background image, color and size of dots, etc.) and select the time range for which you want the image to be generated. The database is updated with data from the newest planet file each week.

The source code for the "history service" is available in the OSM SVN (http://svn.openstreetmap.org/applications/rendering/history/) and is in the Public Domain.