how can I use a GPS to survey land?  How do I find the survey markers
and know their locations realative to the land I am surveying?

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Clarification of Question by dogbrowser-ga on 16 Jun 2005 02:26 PDT

By this, I mean is the longitude and latitude of geodetic markers
"recorded" somewhere so that I can use them to find the location (as
defined by the legal description) of the physical markers?  What I am
trying to "survey" is a large parcel of land (400 acres) in the Texas
panhandle.  I am near a road that is on a section line, so I am
assuming the geodetic makers are somewhere along that road.  I am
further assuming that I can then variance from those to verify (within
a few feet) that the physical markers are correct.  Then I will
compare the physical markers to the fence line to see if there is a
major variance.  The fence line is the legal boundary today, but it
does not precisely follow the physical description.  This land is
rough, rural land where fences are installed by convenience.  It is
impossible to place fences on the true boundary as described in the
legal description of the property.  The fence then becomes the legal
boundary and is the "default" description of the property.  I want to
know how much variance exists between the legal description as
recorded on the deed and the fence.

"Survey markers"?  Do you mean geodetic markers, or the points
mentioned in the description of a land contract?

The latter are not defined in longitude and latitude (which is all a
GPS  device can show).  They are physical markers on the ground, an
iron pipe or other marker that is the corner of one or more parcels
from which compass directions lead to the next point  - by distance or
mention of another marker, and so on until the property line is
defined back to the first marker.

A GPS device could assist in confirming the compass directions and
distances, "back sighting" from the second point to the first one
after both had been entered in the device, and continuing in this way
following the description of the property.

This might reveal errors in the description, the "error of closure" if
the exercise revealed that the description did not result in bringing
the last property line measured back to the original marker.

BUT, GPS devices are not accurate enough to avoid this, so the parcel
description must be accepted, especially since the surveyor who made
it will have checked that it agrees with the descriptions for the
adjacent properties.

HI, I have been travelling.  Thanks for your clarification.

I have not been able to find a site that gives Lat and Long. for
geodetical markers, aka benchmarks, but that does not mean that there
is none for your area.

But I do not think this will help you, since the reference points for
the property will be described physically.  Using GPS to get L & L for
these will allow you to do a rought survey, whereby I found on one
site that GPS coordinates could vary by 2 to 5 meters.  With the
coordinates, you can establish the directions of the lines from one
point to another and calculate the theoretical area  - and possibly
with a surveyor's equipment discover to what extent fence lines
deviate from this  (could be in your favor).

Sorry that I cannot give you more information.  Maybe these two sites
will be of interest.
Myoarin





http://www.akdart.com/bench.html
http://www.intermapper.com/docs/WebHelp/03-using_intermapper/03-01-creating_maps/03-01-03-import-export/using_geographic_coordinates.htm

Myoarin, your links on benchmarks is exactly what I needed.  There is
a benchmark less than 3 miles from the place I want to survey.

Hi Dogbrowser,
I am real pleased that I could help  - and also that you stopped by
again to say so.  You may have some hot legwork ahead.
Good luck, Myoarin