In a message dated 10/5/2003 12:00:07 AM Eastern Daylight Time,
[log in to unmask] writes:
I'm not positive, but to my knowledge, this will be based on mapping =
software.  Find the spot on the map, and then note the coordinates.   I =
have found that the software can be off as little as 10 feet, and as =
much as 1,000 feet.
A GPS receiver will show immediately any error in the map data. As far as
accuracy is concerned I have tested the Earthmate on a USGS trig station and
found the data to be accurate to less than a meter. The test was performed close
to a COORS station which accounts for the great accuracy but an error of 1,000
feet could not be tolerated by the technology of the GPS. Something had to be
wrong in the use of the receiver or in the application software or data to
show such a large error. For example, the map data could easily be in error by
that amount but not the GPS technology.

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