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<font face="Times New Roman, Times, serif">Vector fields would
certainly be very interesting for me. I use them quite a lot when
georeferencing old maps, to indicate the displacements between the
originals and the (rubbersheeted) projected maps. It's not
difficult to do with a PostGIS database, but a standalone
MapServer facility would be quite welcome.<br>
<br>
I'm not sure for how many people this would be useful. It really
has great potential, but old maps are still mostly processed as
archival documents, and the exciting possibilities of exact
georeferencing are not fully recognized. A major reason for that
is that they cannot be realized by predefined buttons in
commercial GIS-systems. A more flexible instrument like MapServer
is much more able to embed this sort of functionality. It's up to
you whether it is worth the trouble to implement it; I would guess
the demand from metereologists would be quite large too.<br>
<br>
To give an impression of the possibilities for old maps, see the
website for MapAnlyst:<br>
<br>
<a class="moz-txt-link-freetext" href="http://mapanalyst.cartography.ch/">http://mapanalyst.cartography.ch/</a><br>
<br>
and Petr Pridal's web site on georeferencing old maps. <br>
<br>
<a class="moz-txt-link-freetext" href="http://help.oldmapsonline.org/georeference">http://help.oldmapsonline.org/georeference</a><br>
</font><br>
<br>
<br>
On 06/28/11 22:13, Daniel Morissette wrote:
<blockquote cite="mid:4E0A35FC.2040204@mapgears.com" type="cite">Hi
Devs,
<br>
<br>
We've been asked about the possibility to add support for
rendering vector fields in MapServer. I don't think that would be
very complicated, but before answering I'd like to gauge interest
from others in seeing this feature in MapServer.
<br>
<br>
Vector fields are used for instance in meteorology to
store/display wind direction and magnitude. The source is two
single-band raster images, one band represents the U component of
the vector, and the 2nd band the V component.
<br>
<br>
Using the u,v values at a given location we can compute a rotation
and magnitude and use that to draw an arrow of a size proportional
to the magnitude and pointing in the direction of the phenomenon
(wind, current, etc.)
<br>
<br>
Wikipedia has a nice figure showing what I'm talking about:
<br>
<br>
<a class="moz-txt-link-freetext" href="http://en.wikipedia.org/wiki/Vector_field">http://en.wikipedia.org/wiki/Vector_field</a>
<br>
<br>
Would there be interest in seeing support for vector fields added
to the MapServer core? Has anyone done work on that front already?
<br>
<br>
Daniel
<br>
</blockquote>
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