Ellie: Plot GPS elevation profiles (Shallow Thoughts)

Akkana's Musings on Open Source, Science, and Nature.

Tue, 03 Mar 2009

Ellie: Plot GPS elevation profiles

Ever since I got the GPS I've been wanting something that plots the elevation data it stores. There are lots of apps that will show me the track I followed in latitude and longitude, but I couldn't find anything that would plot elevations.

But GPX (the XML-based format commonly used to upload track logs) is very straightforward -- you can look at the file and read the elevations right out of it. I knew it wouldn't be hard to write a script to plot them in Python; it just needed a few quiet hours. Sounded like just the ticket for a rainy day stuck at home with a sore throat.

Sure enough, it was fairly easy. I used xml.dom.minidom to parse the file (I'd already had some experience with it in gimplabels for converting gLabels templates), and pylab from matplotlib for doing the plotting. Easy and nice looking.

I even threw in the nice "conditional main" code from Matt Harrison's SCALE7x Python talk, so it should be callable from other Python code.

Here's the page and a screenshot: Ellie: plot elevation from a GPS track.

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[ 16:57 Mar 03, 2009    More programming | permalink to this entry ]