From:
bob_renner@cirilium.com
Sent: 9/19/2000 10:58:55 AM
To:
gpsstash@egroups.com
Cc:
Bcc:
Subject:

Re: [gpsstash] utm versus lat/lon



There is really very little difference to using UTM and lat/long on maps.
Both systems
give you a n/s and e/w reference. The main reason for the popularity of
UTM is that
many topo maps are coming with the UTM grid preprinted on the map. Some
topo maps
had the lat/long grid preprinted, but the grid was 2.5min x 2.5min. This
is also what is
marked in the margins of the maps. This is TOO big to accurately locate
your position.

If the grid was printed at 1min x 1min, then you would have a very similar
grid to the UTM.
I agree that the lat/long grid would be larger and rectangular whereas the
UTM is smaller
and square, but it would provide a very similar feature as far as position
location is
concerned. You would then set your gps to DD MM.MMM (not DD MM SS or
DD.DDDD).

If either grid were to be printed even finer (e.g. 100m x 100m or 0.1min x
0.1min) you
would get a grid that would be even easier in position location, but the
map would start
to get too cluttered.

Another advantage to the UTM is that you can get a square clear plastic
ruler with the
UTM measurements that match the USGS maps and use it to interpolate your
position.
However, if you are using a computer printout map, then the scale most
likely does not
match.

If you have a computer map program (such as Topo!), try printing a map with
a grid of
1min x 1min, set your gps to DD MM.MMM and give it a try. The DD MM.
portion tells
you which rectangle you're in, and the .MMM portion tells you where you are
in the
rectangle - very similar to UTM. What you eventually end up using is all a
matter of
personal preference.

I tend to NOT use the gps number output. I will set up waypoints for a
hike on the computer
before I go out. I then use the map screen on the gps to show me my
position relative to
the waypoints. I then try to pinpoint my position by the surrounding
terrain on the paper
map. This works for me and it worked last Sunday in finding a GPS Stash ;
-)
(I think you hid the additional bottle too well).

Bob



does anyone else use utm for their position format with their gps. i
use a garmin 12xl for my hikes and carry paper maps. i can find my
position very accurately on a map with utm.