i find it useful to separate the gpx track files by sortie. this allows for review of the individual flights (i use delorme street atlas), without much filtering using gpsbabel, and allows for quick selection of the pertinent photo time period for robogeo. i have posted an apparent problem with the track time frame filtering local/gmt checkbox elsewhere on this forum.
i dont have a lot of faith in the gps on board the cam, and have been using a garmin foretrex 401 as a dependable source of track info. the instruction book that came with the camera's gps cautions against use in automobiles, i'm guessing aircraft are affected also.
i recently bought an etrex 30 and have found that the stopwatch function generates individual separate gpx files for the duration of the run of the stopwatch. once reset, the stopwatch can be started again at the beginning of the next sortie. the files are easily distinguishable, because the start time, in local time, is part of the file name. there is plenty of room in memory for the two second sampling rate.
is anyone else using the etrex series in this manner, and have u found any useful tricks? i think the other extrex models also have a stopwatch function, and will check and see if it functions as the 30.