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<font face="Times New Roman">For the Dutch case: in 2005 the
PROJ-definition for the Dutch national system (which uses "Double
Stereographic") was changed from "stere" to "sterea". See the
thread starting at:
<a class="moz-txt-link-freetext" href="http://lists.osgeo.org/pipermail/gdal-dev/2005-November/007045.html">http://lists.osgeo.org/pipermail/gdal-dev/2005-November/007045.html</a></font>.
The thread refers to a bug ticket at
<a class="moz-txt-link-freetext" href="http://bugzilla.remotesensing.org/show_bug.cgi?id=980">http://bugzilla.remotesensing.org/show_bug.cgi?id=980</a>, but that link
doesn't exist anymore. <br>
<br>
Is there a place to put al the links on the stere-sterea subject
together? In my experience, discussions about projection parameters
tend to get fragmented, and even if a solution has been found, old
errors tend to show up time and again. Sometimes, I can only find
the solution in my private email archive. <br>
<br>
Jan<br>
<br>
On 2011-02-07 11:32, Maciej Sieczka wrote:
<blockquote cite="mid:4D4FCA3B.5010405@sieczka.org" type="cite">W
dniu 05.02.2011 14:47, Hermann Peifer pisze:
<br>
<blockquote type="cite">On 05/02/2011 13:12, Even Rouault wrote:
<br>
</blockquote>
<br>
<blockquote type="cite">
<blockquote type="cite">I've just had a look, but not being
neither Dutch nor a specialist
<br>
of (stereographic) projections, I don't feel competent enough
to do
<br>
any action on it. Those tickets plus the reading of
<br>
<a class="moz-txt-link-freetext" href="http://udig.refractions.net/files/docs/api">http://udig.refractions.net/files/docs/api</a>-
<br>
geotools/org/geotools/referencing/operation/projection/Stereographic.html
<br>
make me deeply confused and wondering if r21627 was really
<br>
appropriate.
<br>
</blockquote>
</blockquote>
<br>
<blockquote type="cite">Hmm. This page confirms what I mentioned
in ticket #2869:
<br>
"Double_Stereographic" is simply the ESRI alias of
<br>
"Oblique_Stereographic" (EPSG code 9809).
<br>
<br>
About r21627: I am afraid I do not understand enough about the
inner
<br>
workings of GDAL/OGR to make a judgement about whether this
change
<br>
was appropriate or not.
<br>
<br>
But by the end of the day and from what I remember when looking
<br>
somewhat deeper into the issue, about 2 years ago: there is one
<br>
stereographic projection (known as "the USGS formula" or "the
<br>
approach given by Snyder") which translates into +proj=stere,
and
<br>
there is the other "Double_Stereographic", aka
<br>
"Oblique_Stereographic" which is expected to end up as
+proj=sterea.
<br>
</blockquote>
<br>
I'm not an expert too, but Hermann findings are in accordance with
my
<br>
findings for Polish stereographic CRS (from over 5 years ago):
<br>
<br>
<a class="moz-txt-link-freetext" href="http://lists.maptools.org/pipermail/proj/2005-March/001524.html">http://lists.maptools.org/pipermail/proj/2005-March/001524.html</a>
<br>
<br>
The Polish CRSs which use +proj=sterea version of stereographic
are
<br>
3120, 2172-2174, 3328.
<br>
<br>
See also Gerald Evendeen's notes:
<br>
<br>
<a class="moz-txt-link-freetext" href="http://lists.maptools.org/pipermail/proj/2005-March/001526.html">http://lists.maptools.org/pipermail/proj/2005-March/001526.html</a>
<br>
<br>
Maciek
<br>
<br>
</blockquote>
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