Wednesday, January 30, 2008
GPS Tracklogs...use them.
I have spent the last 7 days doing field mapping in southern Nevada and fine-tuning some new and simple digital methods. Namely, using the GPS tracklog capability to document my progress, augment my note-taking, and the really cool application of automatic geotagging of field photos (look for related post about that).
GPS tracklogs: Why?
As a field geologist I am enamored with a tool that automatically knows my position in my map area. The handheld GPS is the most useful tool for geologists that has come around in a long time. If you don't use one and prefer to eyeball or triangulate your position the old fashion way, then grab your slide-rule, get on your horse and have at it.
Most of us already know that GPS is great to establish specific waypoints of key observations and sample locations, for example. A GPS tracklog is one step better in that it represents an accurate and complete record of an entire traverse over the course of a day, days, or weeks. Not only is this a useful method of documenting/demonstrating your progress in the field, but it also serves as an important complement to note taking. Once you have traversed a section of your field area, the tracklog will serve as a key reminder of your exact path. In your notes, if you often refer to what was crossed since the last formally recorded waypoint (i.e. SLO, or 'since last observation'), the track-log provides an accurate cartographic representation of exactly where you were since the previous observation (including backtracking to retrieve your forgotten rock hammer). Also, since the track-log can be tuned to record at very short intervals, you can even resort to recording the time of day to link field observations to your track log. Maybe that is too informal, but consider the point that this may be a way to make a quick observation at a time when you don't want to halt the traverse and formally record your position, etc., seeing that you are actually recording it anyway by recording the track log. Another short-hand approach relates to field photographs as described in a subsequent post.