... for recording GPS tracking data is in GPX files (* .gpx). There are lots of programs available for analysis, editing and plotting of GPX files. GPX files are text-based, in XML format, so it's quite easy to parse and extract data from them in your own code. More about the GPX format: http://www.topografix.com/gpx.asp Details of the XML Schema for GPX: http://www.topografix.com/GPX/1 /1/ Here's one of mine, opened in *Notepad++ 2_120500_590000000.png trkpt is a single track point, and you can see it's easy to extract the latitude and longitude figures. I can post a bit of code showing how to do that if you wish? Converting the lat and lon to X,Y co-ordinates for plotting on a screen map at different zoom levels is the tricky bit, involving some maths. You can enter lat and lon directly in OSM to find the map location: 2_120511_430000000.png Note that for most of the UK, longitude is negative. To get some ...