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<font face="Times New Roman, Times, serif">All excellent remarks,
but I'm not sure of nr 1</font><br>
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On 01/21/2013 04:42 PM, Andre Joost wrote:<br>
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<blockquote cite="mid:kdjovd$2a9$3@ger.gmane.org" type="cite">
<pre wrap="">
1) transfer the original coordinates to latlon, without a wgs84 shift
</pre>
<pre wrap="">
Why that? If you want to use the self-defined CRS in Qgis, it should
better be in "real" WGS84 coordinates, that is with the +towgs84
parameters. After all, its the position of the bessel ellipsoid relative
to the WGS84 ellipsoid we now all reference to. Your old CRS may have
the same position, though.
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<font face="Times New Roman, Times, serif">The shift is from the
original ellipsoid to wgs84, so I think the distances should be
computed from different ellipses. I'l try it out next few days.<br>
<br>
If you want, I could send you the proj parameters for the
Tranchot-map, together with the 48 original triangulation points,
both in the original coordinate system and Gauss-Krüger II, as
computed by Rodulf Schmidt in 1973. You can see a rough
georeference (without shifts) at </font><font face="Times New
Roman, Times, serif"> <a class="moz-txt-link-freetext" href="http://mapserver.sara.nl/zl/">http://mapserver.sara.nl/zl/</a>,</font> <font
face="Times New Roman, Times, serif">and the way it did it on:
<a class="moz-txt-link-freetext" href="http://mapserver/conferences/2007/berlin_fossgis/">http://mapserver/conferences/2007/berlin_fossgis/</a>. I'm certainly
going to compute a shift file for it, when I get time for it, but
if you want to try your hand on it, you are very welcome.<br>
<br>
Jan<br>
</font><a href="http://mapserver.sara.nl/zl/"></a>
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