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July 6, 2005
Overlay GPS Tracks onto USGS Topographical maps
Last year, while ATV'ing in the mountains of Colorado, with Robert's help, I figured out how to upload the tracks from my Garmin eTrex Summit GPS into the computer and overlay them on top of the USGS topo maps. It's actually fairly easy, and it's nice to be able to see exactly where you went, without having any guesswork involved.
During your ride, your GPS will automatically track your progress. Mine stores up to 2,000 points in memory. All you need to extract it is 1) a cable and 2) some software. So, I bought the cable for my GPS off of eBay for about $9.00. Then, I downloaded a trial version of ExpertGPS.
Once you download and install Expert GPS, you have to tell it what type of GPS unit you have. Then, you can extract all of the data out of your GPS (waypoints, tracks, etc.). Select File - Save As - and save the file as a .GPX file format.
Go to the website www.gpsvisualizer.com and click on "Draw A Map". Uploade your .GPX file as File #1 and change the settings as follows:
Output Format = .jpg
Max dimension = 1800
Margin = 50
Units = US
Background Map = US: USGS topographic map
Track names = No
Track descriptions = No
Colorize by = Altitude/Elevation
Waypoint names = No
Waypoint descriptions = No
Then click on "Draw the map" and Voila! There you have it. Your tracks superimposed on top of the USGS topographical maps.
If you want to save a copy of the .jpg file, then right-click on the map and then select "Save Image As", and you can save the .jpg file locally.
Note: Be careful with this. It could get you in trouble. For instance, my tracks appear to indicate that I drove an ATV five-six miles down U.S. Highway 285, which would probably be illegal. Needless to say, I didn't do this. It was on my trailer, and I forgot to turn off my GPS. ;)
Seriously, you should be aware that your GPS is tracking you at all times. Even when it's turned off. No joke. When I finish riding, I always take the batteries out of the unit, so it will stop tracking. Otherwise, it fills up the 2,000 track points, and starts deleting them, oldest ones first.
Posted by Peenie Wallie on July 6, 2005 at 7:37 PM