[Gdal-dev] ogr2ogr - more utm zones

[Ed McNierney]

Michele -

The "UTM Projection" isn't really a projection, but a family of related
projections.  Each UTM Zone represents a separate projection; they are
all the same except for the central meridian of the projection.  If your
shapefile extends over more than one UTM Zone, you simply need to choose
which UTM projection (i.e. which zone) you would like to use.  There is
no such thing as a UTM projection spanning more than one zone, although
you can project data "outside" a UTM zone into that zone.  For example,
you can certainly project a shapefile running from 0 degrees longitude
to 18 degrees longitude into UTM Zone 32 even though the data nominally
run from zone 30 through zone 32.  You will begin to get serious
distortion at the edges of the map, and you should be aware that there
are applications in which that error is unacceptable.

	- Ed

Ed McNierney
President and Chief Mapmaker
TopoZone.com / Maps a la carte, Inc.
73 Princeton Street, Suite 305
North Chelmsford, MA  01863
ed at topozone.com
(978) 251-4242 


-----Original Message-----
From: gdal-dev-bounces at lists.maptools.org
[mailto:gdal-dev-bounces at lists.maptools.org] On Behalf Of Sanges Michele
Sent: Monday, October 23, 2006 7:39 AM
To: gdal-dev at lists.maptools.org
Subject: [Gdal-dev] ogr2ogr - more utm zones

Hello everybody,

how do I use the ogr2ogr utility in order to convert a shapefile from
latlon to utm projection, when the file extends in more utm zones?

Thanks.
Michele


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