Hand held gps under trees.

Help. I have the task of marking specimen trees that were planted in the
1850's in woodland. What is the best handheld GPS for marking the spot
bearing in mind that there may be a leaf canopy or do I have to do this in
the winter with less leaves on trees.
Robert

Robert Oliver wrote, On 30/05/2008 14:25:

Leave any consumer GPS handset in full view of the sky and switched on
for 24 hours. When you return there will be a big squiggly track drawing
out a blob about 10-15m or more in diameter. Like you say, the tree
canopy will make things worse, and you can't overcome this error using
normal kit. It depends really how close the trees are, if 50m apart then
it's not a problem I guess.
You see guys on TimeTeam with big 2m lollipop sticks taking accurate
readings. I think that is using differential GPS
(http://en.wikipedia.org/wiki/Differential_GPS ). It probably starts
getting expensive when you want to do serious work.


--
DavidM newsNO@_SPAMdjmorgan.org.uk
www.djmorgan.org.uk

None of them.


Sokkia GSR2700IS, Thales Z-Mac or similar, accurate to 10-50mm in the
conditions that you wish to use a GPS. dGPS will give you accuracy to
around a metre which may not be sufficient for yoru purposes.

This lot hire out surveying GPS, but they do tend to assume you know how
to use one. It does sound from your enquiry that you have been hired to
do something that you don't actually have any experience of doing.

http://www.hiretec.co.uk/

Sorry I have been misunderstood. If the marking is accurate to 5m to 10 m it
would be acceptable. My old Garmin 12 is not good at picking up the
satelites in these conditions and I was looking for something better.
Robert

Any of the modern chipsets would fit your need sirf star 3 etc