myTracks - The GPS - Logger, Dirk Stichling (free:iphone)
I've only had this for a couple of days.
It seems to be fairly accurate, and Ive used it in a place that has no wifi, or phone reception...
*You could probably map your maple trees, by recording while walking along and when you find a tree you want to mark, walk around it a few times.
Each tree would show up as a blobby blue circle in Google earth, you could drop pins to mark and label them.
Contours:
(I haven't done this yet)
Use an a-frame, or other method to mark out a contour.
Start at your first marker, start recording, walk along contour to next marker and so on, stop the recording at the last marker.
Sections and elevations
walking in as straight a line as possible record your track
The app gives you a fair idea of the distance of the slope you walked up/down
The app tells you the highest point and lowest point, so you have the rise and run if you feel like doing some math...
Share/export/email your "track" as a .kml file (this requires a AUD$4.50 upgrade, about USD$2)
Open the .kml file in Google Earth. It becomes a "Path", in the "places" toolbox, left side of screen.
Take a screenshot, which can then be shared/downloaded/exported/printed
You can open multiple .kml files at a time, so you could have a contour map, good enough for illustration purposes at least.
The accuracy is the same as Google Earth paths.
Google earth said max elevation was 96m, my tracks said 92m.
Google earth said min elevation was 88m, my tracks said 82m.
Google earth said my drive way was 144m, my tracks said 150m.
Discrepancies are because the two paths didn't start and finish in exactly the same spot and the google earth path is by default less detailed.
I only walked down my driveway to test it. I think i swung my arms around a bit...
Heres some screen shots.