MEASURING with GPS

["Nancy Mitts" <mitts_n@hotmail.com>]

I'll admit the newer GPS units do make really nifty maps. And I can see the 
value of marking a few waypoints for gadget gurus on rides. I agree strongly 
with KAT's points about the danger of riding with your eyes on a 
gadget--it's enough of a problem for me I don't even use an on board heart 
monitor anymore--too distracting.
What I find really scary is ride managers using GPS for trail measurement. 
These trails end up incredibly wrong, typically too LONG. Our trails are 
wooded, in hills, but most important twist & turn back on themselves a lot. 
We're putting trails in land areas of 2000-3000 acres, where the trails are 
just a few feet apart. According to the GPS you know where you are, but 
distance wise you haven't gone anywhere!
We got a unit given to us (magellen 300) that is worthless for 
marking/measuring. (Impractical to manually poke in every change of 
direction, & only has 10 legs in a route) The camp where my ride will be has 
people come in with better ones all the time. The trail boss was riding with 
the guy that writes trail articles for Trail Rider magazine, and his alarm 
(that indicates < 3 satellites) was always going off. Still made a nifty 
map, but the accumulated mileage was way off. It is very entertaining to get 
2 different GPS's riding together & have them come up with different 
mileage.
Truman, get busy with those articles!!!
This past summer a man making maps (ex military, now civilian 
mapmaker)stopped at our place & asked to use our corner post as one of his 
points. It was very interesting to see his set up & we had him explain how 
it worked in great detail. Especially interesting was the scattered dot 
pattern on the stationary unit, and the computer program he would have to 
run it through to come up with an exact "spot". He also mentioned that the 
exact data changes over time. All data must be collected from an area within 
a certain time period. (So collecting data from part of you trail one 
weekend might not be compatable with what you'd get a month later.) We asked 
him about accurately measuring trails through the woods & hills and he just 
shook his head & laughed.

Nancy Mitts



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