-------- Original Message --------
Subject:        Re: High-accuracy GPS
Date:   Wed, 15 Dec 2010 01:20:20 EST
From:   [log in to unmask]
To:     [log in to unmask]



I have a simple suggestion. Sounds almost too simple but has worked for
me. I map individual gravestones in cemeteries with my handheld Garmin.
I set the GPS unit on the stone and wait until it has acquired its
satellites. I take a reading. I wait 8-10 more minutes and take another
reading. Then I wait one more time 8-10 minutes and take a third
reading. The idea being that the satellites are moving around in space
with sometimes more satellites acquired than other times. After three
readings I can "average the data". Most of the time the three readings
are very close to one another with only the most minute differences.

The
downside is that mapping this way takes a long time and it is an
exercise in patience when I use student help. The upside is that I am
not out thousands of dollars for a GPS unit. Barring any interference
such as trying to take readings under tree canopies, readings next to
buildings, or readings next to extensive areas of shiny marble, most of
the time this very simple method works in cemeteries. It might work in
botanical gardens too.

Best Wishes,

Melinda Kashuba
Redding, California


In a message dated 12/14/2010 1:57:04 P.M. Pacific Standard Time,
[log in to unmask] writes:

     -------- Original Message --------
     Subject: High-accuracy GPS
     Date: Tue, 14 Dec 2010 13:31:18 -0800
     From: Dyallen2 <[log in to unmask]>
     To: [log in to unmask]



     Has anybody on this list had experience using high-accuracy GPS? I am
     involved in a GIS project with my local botanical garden, which
requires
     mapping individual plants with sub-meter accuracy. Most systems that do
     this seem to cost upwards of $10,000, which is beyond our reach. I
     stumbled across some information about a DeLorme product called Blue
     Logger GPS, which claims to do this for about $1000. Has anybody had
     success using this system, or have other suggestions for low-cost,
     high-accuracy GPS?
     David Allen
     (retired from Stony Brook University, now volunteering for San Diego
     Botanic Garden)