[R-sig-Geo] location points that span UTM zones

[Glover, Tim]

UTM projects a spherical globe onto a cylinder.  Zones are chosen to
achieve a certain level of accuracy of distances between points.  This
accuracy decreases as you stray from the zone, but is not too bad as
long as you're not too far past the edges of the zone.  "Too bad" and
"too far" are inter-dependent and also depend on your uses of the data.
If you need cm-size accuracy, you don't want to extend half-way into the
next zone, for instance. There is a mathematical relationship between
accuracy and distance from the central meridian of the zone.    



Tim Glover 
Senior Environmental Scientist - Geochemistry 
Geoscience Department Atlanta Area 
MACTEC Engineering and Consulting, Inc. 
Kennesaw, Georgia, USA 
Office 770-421-3310 
Fax 770-421-3486 
Email ntglover at mactec.com 
Web www.mactec.com 
 


-----Original Message-----
From: r-sig-geo-bounces at stat.math.ethz.ch
[mailto:r-sig-geo-bounces at stat.math.ethz.ch] On Behalf Of Corrie Curtice
Sent: Thursday, October 08, 2009 12:13 PM
To: r-sig-geo at stat.math.ethz.ch
Subject: [R-sig-Geo] location points that span UTM zones

Hello,

I have some location data points that span two UTM zones.  I'm using
the points to estimate home ranges, using a couple of home range tools
(NNCH, HRT for ArcGIS).   Can I just project them to the left most
zone, and run the home range tools on that data set?  I'm curious to
know what the negative impacts of this might be.  These are points
around the west coast of Mexico, so UTM 12/13 and 13/14.

Thanks,

Corrie

_______________________________________________
R-sig-Geo mailing list
R-sig-Geo at stat.math.ethz.ch
https://stat.ethz.ch/mailman/listinfo/r-sig-geo