>Date: Thu, 17 Feb 94 14:52:26 +0100
>From: Sven Fuhrmann <sven@linus.uni-muenster.de>
>To: grassu-list@max.cecer.army.mil
>Subject: projection problems
>
>Dear GRASS-user,
>
>Currently I am working with DTM-raster data using GRASS4.1.
>
>The standard region (Mercator) is set to the third central meridian
>(9 degrees = 3,500,000 meters). I would like to project this data to
>the second meridian (6 degrees = 2,500,000 meters) using GRASS4.1.
>
>Does anyone has knowledge of a GRASS4.1 command performing this kind
>of projection for the whole rastermap?
>
>I do appreciate any idea to solve this problem and I thank you
>in advance for helping me.
>
>Marie Luelff
>marie@linus.uni-muenster.deThis message seems to contain several problems:
(1) "standard region (Mercator)"---what standard? GK, UTM? If either
than please use Transverse Mercator, not simply Mercator.(2) If the reference is to the GK system, then I do not believe that
there is any 6 degree meridian. They should be 3, 9, 15E, ...,
for respective zones 1, 2, 3, ... . The false eastings seem to
fit GK usage but the central meridian does not.Note: I am using GK in the sense of the old Eastern block equivalent
to UTM, not the computation method (equivalent to that used in UTM).Gerald (Jerry) I. Evenden Internet: gie@charon.er.usgs.gov
voice: (508)563-6766 Postal: P.O. Box 1027
fax: (508)457-2310 N.Falmouth, MA 02556-1027
I think Marie is referring to Gauss-Krueger, wchich is Transverse Mercator,
and in Germany there is a 6 degree Meridian, which has a false easting of
2500000. The false easting value in Germany is 500000 , the zones are in
steps of three degrees, thus 2500000=6deg, 3500000=9deg, 4500000=12deg, etc.
If there is a r.proj that can be used, if not produce an ascii file with
r.stats and use proj4.1. to convert, import the result with s.in.ascii and
convert the sites file to raster.
Stefan J.
Dept. of Geogr., Univ. of Heidelberg
Germany
currently USGS, Reston, VA
sjaeger@resdgs2.er.usgs.gov