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<DIV><FONT size=2 face=Arial>John:</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>I appreciated your astute "back of the envelope"
approach of quantifying Google Earth accuracy -- that is, establishing
ground-truth with averaged GPS measurements and then comparing with Google Earth
data.</FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<DIV><FONT size=2 face=Arial>Regards,</FONT></DIV>
<DIV><FONT size=2 face=Arial>Kevin</FONT></DIV>
<DIV>************************************************<BR>Manager, Integrated
Systems Group<BR>System Dynamics International, Inc.<BR>9116 SW 51st Road, Suite
102<BR>Gainesville, FL 32608<BR>Phone/Fax: (352) 371-8035<BR><A
href="http://www.sdi-inc.com">www.sdi-inc.com</A><BR>*************************************************</DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=John.Sykes@dep.state.fl.us
href="mailto:John.Sykes@dep.state.fl.us">Sykes, John</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=aknight@fnai.org
href="mailto:aknight@fnai.org">'Amy Knight'</A> ; <A
title=shrug-l@lists.dep.state.fl.us
href="mailto:shrug-l@lists.dep.state.fl.us">shrug-l@lists.dep.state.fl.us</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Friday, March 08, 2013 9:27
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: shrug-l: Google earth
accuracy estimate?</DIV>
<DIV><BR></DIV>
<DIV>
<DIV>
<DIV>
<DIV class=WordSection1>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">There are errors when using
Google Earth or Google Maps to plot lat/longs in Florida. But in my
experience they are relatively minor, because Florida is FLAT! In my
experience elevation differences cause many if not most of the errors.
The major problems I see involve plotting addresses, where things may be off
by half a block. If you find the particular building and plot it, it
usually is accurate to about 10 meters or better. Part of the error
comes from the aerials used and how well they were georeferenced. Since
most aerials for the State are now being flown with a digital linear scanner,
they are much less prone to these errors.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d"><o:p> </o:p></SPAN></P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d">I just checked my own home,
where I have a very visible location on my back deck that I have used to check
several GPS’s for accuracy. Pulling the Google Earth lat/long quickly
(they have a brand-new aerial, shot only a few months ago) and comparing it to
the GPS average was within 1 meter. T’ain’t too shabby! Probably 1
ft of that error is my shaky hand on the trackball. Oh, by the way, they
weren’t survey-grade GPS’s either; 1 Garmin, 1 DeLorme and my roommate’s
TomTom. But I took several readings on different days and averaged them
out.<o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN style="COLOR: #1f497d"><o:p> </o:p></SPAN></P>
<DIV>
<P class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Brush Script MT'; COLOR: #1f497d; FONT-SIZE: 24pt">--
John</SPAN></B><SPAN style="COLOR: #1f497d; FONT-SIZE: 24pt">
<o:p></o:p></SPAN></P></DIV>
<P class=MsoNormal><SPAN style="COLOR: #1f497d"><o:p> </o:p></SPAN></P>
<DIV></DIV>
<DIV><BR><BR></DIV>
<DIV style="FONT-FAMILY: Courier New; FONT-SIZE: 9pt"><EM><FONT size=2
face=Arial>Please take a few minutes to share your comments on the service you
received from the department by clicking on this link <A
href="http://survey.dep.state.fl.us/?refemail=John.Sykes@dep.state.fl.us"
target=_blank>DEP Customer Survey</A>.</FONT></EM></DIV>
<DIV style="FONT-FAMILY: Courier New; FONT-SIZE: 9pt"><EM><FONT size=2
face=Arial></FONT></EM></DIV>
<DIV style="FONT-FAMILY: Courier New; FONT-SIZE: 9pt">
<P class=MsoNormal><B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; FONT-SIZE: 10pt">From:</SPAN></B><SPAN
style="FONT-FAMILY: 'Tahoma','sans-serif'; FONT-SIZE: 10pt">
shrug-l-bounces@lists.dep.state.fl.us
[mailto:shrug-l-bounces@lists.dep.state.fl.us] <B>On Behalf Of </B>Amy
Knight<BR><B>Sent:</B> Thursday, March 07, 2013 10:55 AM<BR><B>To:</B>
shrug-l@lists.dep.state.fl.us<BR><B>Subject:</B> shrug-l: Google earth
accuracy estimate?<o:p></o:p></SPAN></P></DIV></DIV>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal>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-<o:p></o:p></P>
<P class=MsoNormal>Amy <o:p></o:p></P>
<P class=MsoNormal><o:p> </o:p></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #1f497d; FONT-SIZE: 8pt">Amy
Knight</SPAN><SPAN style="FONT-SIZE: 8pt"><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #1f497d; FONT-SIZE: 8pt">GIS
Program Specialist</SPAN><SPAN style="FONT-SIZE: 8pt"><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #1f497d; FONT-SIZE: 8pt">Florida
Natural Areas Inventory</SPAN><SPAN
style="FONT-SIZE: 8pt"><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: #1f497d; FONT-SIZE: 8pt">Florida
State University</SPAN><SPAN style="FONT-SIZE: 8pt"><o:p></o:p></SPAN></P>
<P class=MsoNormal><SPAN
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Thomasville Rd, Suite 200-C</SPAN><SPAN
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850-224-8207 x214</SPAN><SPAN style="FONT-SIZE: 8pt"><o:p></o:p></SPAN></P>
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href="http://www.fnai.org">www.fnai.org</A></SPAN><SPAN
style="FONT-SIZE: 8pt"><o:p></o:p></SPAN></P>
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<P></P>_______________________________________________<BR>SHRUG-L mailing
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