OpenStreetMap: the data behind the maps
In my last article on OpenStreetMap I looked at the recent mass imports of public data — everything from British oil wells to the entire road network for the United States. But for those interested in more than an alternative to Google Maps, the ability to extract or add data to the project is what really makes OpenStreetMap shine. Whether you want to get an SVG of a campus map or import a local government's database of every building in the city, Linux users will find plenty of tools that cater to their needs.
The export tab on the web site provides the most simple way to access data. Users can draw an area on the main map view and then grab an image (in PNG, JPEG, PDF or PS formats); some HTML to embed the map into your web site; or the raw XML data. To further modify the data, either in the OpenStreetMap database or a local copy (stored as an XML .osm file on your disk) download the data using an editor like JOSM (the 'Java OpenStreetMap editor'). To make life easier when selecting the area to download, open up the preferences dialog and install the namefinder and slippy_map_chooser plugins.
Grabbing larger amounts of data would be difficult, slow and clumsy with these methods. More advanced users can get data directly through the API. Check the latitude and longitude coordinates for the area you want — an easy method for this is to use the export tab to draw an area, then note down the coordinates it records — then fire up wget or curl and download the data:
Read More...http://lwn.net/Articles/322163/
OpenStreetMap
http://www.openstreetmap.org/
Don
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