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[CDT-L] GPS overkill?
- Subject: [CDT-L] GPS overkill?
- Date: Sat, 19 Feb 2000 20:35:35 -0500
It was stated here that a GPS is overkill, and more of a toy, not a
serious insturment to use while hiking. I couldn't disagree more.
Probably, someone said something like that when maps and compasses were
invented, "I know my stars and landmarks to navigate, I don't need those
new fangled land drawings and floating neddles." All methods and
knowledge of navigation are useful, sometimes you must use all on some
type of hike, sometimes none. A GPS is an extention of navigation.
First of all when hiking, its best to use a GPS with a regular compass
(or electronic one) and a map(s). Unless you want to record a track for
future use (upload it to your computer later) its best to turn it on get
your bearing, turn it off, and use a compass in between, turing on the
unit when you think it's necessary.
The main trick I've found is to preprogram waypoints before a hike. This
can be done using mapping apps, or there is a USGS site on the web, that
you enter a state and quad name, it returns many waypoints in that quad.
Use them as direct points or reference. You can get free state published
map catalog from the USGS, showing quad names, there are places on the
web to get freee topos.
With a compass and map, you must orient both to true or mag north, to
plot a direction from the map, or from a sighting. With a GPS you must
orient a map,but the unit will give you direction. The disavantage is
that you must be moving to get a direction from a GPS.
You have to use the map scale to plot a distance, a GPS will tell you it.
Both are "as the crow flies. If a mountain is between point A and B,
neither is going to add the elevation gain and loss between, that's what
the contour lines (if you have them, many FS maps don't) tell you.
With a compass, to find the point your at now, you must at least take at
least two bearings to landmarks, match them to the map and bisect
them.(Do that in a forest) With a GPS just turn it on, you got location,
match Lat\Long or UTM to the map.
Most compasses won't read to a accuracy of + or - 1degree. That means in
a mile, you could have 92 feet of lateral error. Coupled with sometimes,
mag declination is not stable, and/or as shown on a map, average for an
area, you must use reference features to navigate. If you lose sight of
those, you have no means of determining if you drifted laterally or not.
To check lateral drift with a GPS, just turn it on, the CDI will show
you they way to move to the waypoint, even if you passed it and have to
backtrack, try doing that just with a compass and map! Usally, a GPS
within a 100 or 300 ft of a point, a lot more accurate than a compass,
especially over long distances. As with compass navigation, bracketing a
point to reach using GPS is desirable(the waypoints on quads I mentioned
Just remember maps have errors on them (USGS quads claim accuracy of a
100 feet). With a compass and map you still plot to that water source.
Preprogram the water waypoint in you GPS, it might not be there, either
way. A line with a pencil on a map might be .02 thick, thats 40 to 100
feet of ground distance error, depending on map scale!
To sum up, a GPS will also serve up ETA, ETA, UTC, moon & sun phases,
closer info, DOF, and many other features, much more than a compass.
Worried about getting lost hurt(I get never lost, I'm just in a different
place than I was supposed to be)? Get a GPS cellphone, that way you can
tell someone, and give them directions to boot! Or get a Palm with GPS,
you also got all your other info stored.
I know some will still say the hell with a GPS, its to modern for me, I
got my compass skills. Well, which buried skier might be saved first, one
with a locator beacon, or without (modern gear)? The route up Mt Everest
is known, but GPS and beacons are used there. Why are you using modern
boots, tent, backpack, sleep bag, instead of leaves on da foots, building
shelter on a trail, wiker basket pack, a plain blanket? One word,
Convenience! Same same GPS.
0 AT 87-88
|- FT 89
| PCT 90-91
/^\ NCT 92-95
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