Thursday, January 31, 2008

GPS Tracklogs for Dummies

In order to learn more about tracklogs on your GPS, simply break down and read the short manual that came with the unit. If your unit is more that 3 years old or uses more than 2 AA batteries, you should upgrade. One important consideration is upgrading to a unit that has a memory card slot. In that case, you will be able to store considerably more data. In the case of my Garmin GPS 60csx, interacting with the memory card is actually easier than interacting with the unit. Also, it automatically creates individual logs on a per day basis. Very handy.

Please, please (!) rid yourself of the belief that you need to turn the unit off all of the time to save batteries. Newer units can run for 2-4 days on a single set of batteries when turned on and off at the beginning and end of the field day. If you are worried about wasting batteries, then use rechargeable ones and move on, man. In order to maximize the value of the track log, the unit should remain on during the entire day (except during lunch, when you change batteries, or when you are mapping underground).

A colleague at NBMG recently turned me on to a very handy program from the Minnesota Department of Natural Resources that easily converts GPS tracklogs and waypoints to shapefiles to use in GIS software. The program is called DNR Garmin and is extremely handy. Kudos to the author. The program can suck data right off the unit or can read from a gpx file. The image above is proof that it works.

1 comment:

Leszek Pawlowicz said...

The Garmins with memory cards are fantastic - I love my 60Cx. But they won't "automatically" log your tracks into the memory card until you set that option in the "Setup" menu. Otherwise, the track will only be saved in the active track, which has a 10,000 point limit if you have no saved tracks, and 500 points less for every named track you've saved on the track page. After you hit the limit, it will delete the oldest points automatically.

Also, if you save the active track as a named track, and it has more than 500 points, it will be simplified down to 500 points maximum, which can remove significant amounts of detail. Finally, as I learned rather painfully, tracks saved as named tracks strip out the time data, so you can't use them for automated geotagging with GeoSetter. Only the active track keeps the time data. Another reason to use the option that logs all your tracks to the memory cards, since that preserves the tracklog's time data.

Wish I were doing field work in Nevada :).