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Elders Grove and the Garmin Oregon 450t

Posted: Wed May 26, 2010 8:21 am
by dbhguru
ENTS,

Yesterday, I went to the Elders Grove to use my new Garmin Oregon 450t to create a map for DCR of the locations of 27 white pines and to identify the trail through the grove. Well, the Garmin proved useful, but also fell short. The following map was created from the GPS coordinates of the trees. However, the track representing the trail through the grove was off, so I had to overlay the approximate route. It is not clear why the track was so far off, but it was. It maybe that when one walks a path with the tracking feature active, the accuracy drops significantly. I have tested the Garmin on 4 tracks so far and have not gotten an accurate track yet. Lots more testing to do.
EldersGroveTrack.png

BTW, Saheda is now up to 166 feet! The next image show this incredible pine. Saheda is 50.6 meters tall and is only one of 4 white pines measured in New England to surpass 50 meters. Fifty meters is equivalent to 164.04 feet. One hundred and fifty feet is equivalent to 45.72 meters. We've documented plenty that reach that threshold, but 50 is a very, very exclusive club. Viva la Saheda.
SahedaSmall.jpg

Bob

Re: Elders Grove and the Garmin Oregon 450t

Posted: Wed May 26, 2010 3:04 pm
by Gary Beluzo
Bob,

The accuracy varies according to position relative to topography, horizon, satellite PDOP, etc. I found that if I did differential correction with the Mt. Holyoke website then most of my points were fairly accurate. Did you have WAAS on? Does your unit do real-time differential correction?

Gary

Re: Elders Grove and the Garmin Oregon 450t

Posted: Wed May 26, 2010 3:21 pm
by dbhguru
Gary,

Not to my knowledge. I didn't read anything in the literature on applying corrections. I remember you doing all that when you took that expensive system from the college out into the woods.

Bob