Lines and boundaries

[rval...@persona.ca]

For those of you who have ever marked or flagged lines or boundaries
with GPS in whatever cover (light to heavy). I would be interested to
know what your procedure was, what your results were, what brand and
type of receiver used and whether or not an external antenna was used?

[Dan Anderson]

I map trails (a form of lines). The best sky view has been on top of
narrow mountain peaks over 14,000 feet. The worst in narrow, wooded
canyons where a position lock is not made when there is a lack of
overhead satellites (I've yet to be in a slot canyon in Utah with
a receiver.).

Currently I use three receivers - Garmin 76Cx, 76CSx, and 76S.
Those give me two sets of elevation data from barometric altimeters and
one set from GPS. Also I get two sets of horizontal data from sensitive
receivers and one set from a less sensitive receiver. The less sensitive
receiver (76S) isn't affected as much by multipath so does better in
some environments. The 76S is connected to an external antenna mounted
on a hat or helmet.

There's some more information at www.gpsmap.net
particularly under tests. "Results" are hard to answer because it
depends on the environment. Also, the 76CSx, which was bought a year
after the 76Cx, seems to track more consistently than the 76Cx. They
both have the same SiRF III firmware.

The "x" models are set to record a point every second. The 76S is
set to record every two seconds in most cases.

I hand hold the 76Cx and the 76CSx is mounted on a post connected
to my pack. I do what I can to keep my body from blocking the sky
view and I pay attention to the satellite constellation especially
when gathering data in narrow canyons.

Wind effects the altitude data from the barometric altimeters -
effectively reduces fine resolution.

--
Dan

Personal: www.gpsmap.net
Business:
Western Maps LLC
www.westernmaps.us

[John Tyson]

<rval...@persona.ca> wrote in message
news:0de984de-8c21-4af8...@l64g2000hse.googlegroups.com...

You may find this recent thread on the Groundspeak forum interesting:

http://forums.groundspeak.com/GC/index.php?s=984e6c3bda9db99be63b6ab185bedf30&showtopic=204773

John