shrug-l: Google earth accuracy estimate?

Jim Robeson jim at
Fri Mar 8 09:31:02 EST 2013

I would say the accuracy for the location of an endangered species would be
acceptable.  The problem might be more of individuals who have no or little
photo interpretation experience placing a point in an area with little of no
ground features to accurately identify their location on the image.   As for
a number, I don't have one.  A lot might depend on their level of support on
Google Earth; are they paying for the upgraded version?  


There is the old cartographic trick and that is make the point symbol sized
proportionally to the confidence in the data accuracy and quality.    A
point that is 200 feet across covers a lot of sins;  the same with a 200
foot wide line.   The is the modern day equivalent to using a magic marker
of a blue line map.   Most never realized that, that line could be a couple
hundred feet wide.  


So, sadly I don't have any numbers on Google Earth.  I suspect given the
kinds of errors that we all shared, any number might be rather dubious.  



Jim Robeson


James M. Robeson

Mapping/GIS Sales, Trimble Certified Trainer  


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From: shrug-l-bounces at
[mailto:shrug-l-bounces at] On Behalf Of Amy Knight
Sent: Thursday, March 07, 2013 10:55 AM
To: shrug-l at
Subject: shrug-l: Google earth accuracy estimate?


Hi-  A year or so there was SHRUG exchange of 'bad' google earth examples.
Does anyone know of an accuracy estimate for Florida?  We receive point
location data from many different sources but more and more data are coming
in with Google Earth as the source of the location (lat/long).   We need to
be able to say what locational uncertainty those data have.   How 'off'
could a point be, plotted on Google Earth vs. Florida aerial ortho imagery?
Thanks for any information-



Amy Knight

GIS Program Specialist

Florida Natural Areas Inventory

Florida State University

1018 Thomasville Rd, Suite 200-C

Tallahassee, FL 32303

Ph. 850-224-8207 x214

Science for Conservation


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