Making Google Maps from a GPS track

It can hardly have escaped most people’s attention that Google Maps is an incredibly useful tool.  I just used it to plan my summer holidays, marking where we are staying, places to visit, routes to take and so on. I did this using the My Maps feature, available through a Google Account, which lets you annotate and edit a map. What may not be so obvious to new users is that you can save the map as KML by using the link URL. and adding “&output=kml” to the end.

More interestingly, you can import KML files into My Maps in Google Maps, which adds extra  possibilities. I exploited this when I made a map of the running route for the Red Nose Day Run we are doing. You can see the result at http://maps.google.co.uk/maps/ms?ie=UTF8&hl=en&msa=0&msid=113734510941254986423.000462ba294a2a1373c9f&z=14. I created this by travelling the route wearing a GPS-enabled watch (the excellent Garmin Forerunner 305), and converting the resulting track record to KML (using a program called Ascent on my Macintosh).

All well and good, but the Forerunner had recorded a point every few metres, and that was too much for me to further edit by hand. I was able to get a much neater result by smoothing the KML using the “simplify” filter of the excellent gpsbabel (http://www.gpsbabel.org/) utility. This removed all points which did not make more than 10 metres of difference. Now I could upload the filtered map to Google Maps and refine the route by using it as a KML editor. Now I have to actually run the route – rest assured that we’ll be tracking what we actually do using a variety of GPS tools.

Of course there are a 1001 tools out there for editing KML, making map-based visualizations, plotting routes, and so on. I’m just talking about casual use here. But the extreme ease of performing tasks like this shows that there is no excuse for not getting into geolocating things in your life.

One Response to Making Google Maps from a GPS track

  1. Forrest says:

    I’ve yet to really get into KML, but know that I can’t avoid it much longer.

    So far I’ve been loading my GPX files directly into Google Earth when I want impressive visualization, and I’ve been loading them also into a program called SportTracks for most other reasons. ( That’s sort of a “where you’ve been and what you did” database. )

    I also use the GPS track logs for geo-coding photos. The best of these wind up on my personal blog ( when I have time in front of the computer ) and I fight WordPress, using Google Maps javascript code, with hand-written custom code for push pins and the like. I know that KML would make this drastically easier – and this will have to be a “sooner than later” project for me.

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