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Norman,<br>
<br>
Many thanks for the link; it's good to see how others have
approached the problem. The font referenced is an ESRI font so I
don't think I can use it due to copyright, but perhaps I could
construct my own using the same glyph indexes for compatibility.<br>
<pre class="moz-signature" cols="72">Best Regards,
Brent Fraser</pre>
<br>
On 9/27/2011 12:09 PM, Norman Vine wrote:
<blockquote cite="mid:9256BAB6-D33D-407A-9718-B3B4F24EFAB8@cape.com"
type="cite"><br>
<div>
<div>On Sep 27, 2011, at 2:03 PM, Paul Ramsey wrote:</div>
<br class="Apple-interchange-newline">
<blockquote type="cite">
<div>Once you have vectors, the classic trick I've seen for
doing the barbs<br>
is to do math to map the windspeed into an appropriate
char() value<br>
and store the barbs as TTF font entries. So you only end up
with one<br>
class, and the barb is an appropriately rotated label.<br>
</div>
</blockquote>
<div><br>
</div>
<div>This might help</div>
<div><a moz-do-not-send="true"
href="http://carocoops.org/bb/viewtopic.php?t=169">http://carocoops.org/bb/viewtopic.php?t=169</a></div>
<div><br>
</div>
<div><br>
</div>
<blockquote type="cite">
<div><br>
P.<br>
<br>
On Tue, Sep 27, 2011 at 10:31 AM, Brent Fraser <<a
moz-do-not-send="true"
href="mailto:bfraser@geoanalytic.com">bfraser@geoanalytic.com</a>>
wrote:<br>
<blockquote type="cite"> At FOSS4G I was struck by the
number of presentations involving weather<br>
</blockquote>
<blockquote type="cite">data and time series display. Maybe
I noticed because I have a need to<br>
</blockquote>
<blockquote type="cite">render wind velocity in KML, and
while I haven't settled on mapserver to do<br>
</blockquote>
<blockquote type="cite">the rendering I've been wondering
how to render wind barb symbols (see<br>
</blockquote>
<blockquote type="cite">attached graphics) efficiently.<br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite"> One problem is the source data: the
magnitude is in one raster file (GRIB<br>
</blockquote>
<blockquote type="cite">format, float64) and the direction
in another. GDAL's OGR library will<br>
</blockquote>
<blockquote type="cite">read the GRIB files, but I don't
know of any way to use two rasters to<br>
</blockquote>
<blockquote type="cite">define a vector layer. I think
there is some work going on with respect to<br>
</blockquote>
<blockquote type="cite">displaying vector field data in
mapserver, so maybe this will be solved by<br>
</blockquote>
<blockquote type="cite">that work. Otherwise pre-processing
the two rasters into a point datasource<br>
</blockquote>
<blockquote type="cite">containing lon,lat,speed,direction
attributes may be the way to go.<br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite"> The other issue of wind barb symbol
rendering may have to be solved by hand<br>
</blockquote>
<blockquote type="cite">constructing a barb for 0 knots, 5
knots, etc (50-ish symbols?) , and having<br>
</blockquote>
<blockquote type="cite">50-ish corresponding classes (this
could be a performance problem for<br>
</blockquote>
<blockquote type="cite">mapserver). But I'm open to better
ideas... SLD? HTTP/CGI request?,<br>
</blockquote>
<blockquote type="cite">something like one class of:<br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite"> CLASS<br>
</blockquote>
<blockquote type="cite"> STYLE<br>
</blockquote>
<blockquote type="cite"> GEOMTRANSFORM "start"<br>
</blockquote>
<blockquote type="cite"> COLOR 0 255 0<br>
</blockquote>
<blockquote type="cite"> SIZE 15.0<br>
</blockquote>
<blockquote type="cite"> SYMBOL "<a
moz-do-not-send="true"
href="http://localhost/symbolgen?[speed]">http://localhost/symbolgen?[speed]</a>"<br>
</blockquote>
<blockquote type="cite"> ANGLE [direction]<br>
</blockquote>
<blockquote type="cite"> END<br>
</blockquote>
<blockquote type="cite"> END<br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite"> but likely the cost of getting the
symbol would be greater that creating 50<br>
</blockquote>
<blockquote type="cite">separate class objects.<br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite">And for those interested in mapping
and graphing weather data, have a look<br>
</blockquote>
<blockquote type="cite">at <a moz-do-not-send="true"
href="http://www.ncl.ucar.edu/Applications/">http://www.ncl.ucar.edu/Applications/</a><br>
</blockquote>
<blockquote type="cite">especially <a
moz-do-not-send="true"
href="http://www.ncl.ucar.edu/Applications/barb.shtml">http://www.ncl.ucar.edu/Applications/barb.shtml</a><br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite">--<br>
</blockquote>
<blockquote type="cite">Best Regards,<br>
</blockquote>
<blockquote type="cite">Brent Fraser<br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite">_______________________________________________<br>
</blockquote>
<blockquote type="cite">mapserver-users mailing list<br>
</blockquote>
<blockquote type="cite"><a moz-do-not-send="true"
href="mailto:mapserver-users@lists.osgeo.org">mapserver-users@lists.osgeo.org</a><br>
</blockquote>
<blockquote type="cite"><a moz-do-not-send="true"
href="http://lists.osgeo.org/mailman/listinfo/mapserver-users">http://lists.osgeo.org/mailman/listinfo/mapserver-users</a><br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
<blockquote type="cite"><br>
</blockquote>
_______________________________________________<br>
mapserver-users mailing list<br>
<a moz-do-not-send="true"
href="mailto:mapserver-users@lists.osgeo.org">mapserver-users@lists.osgeo.org</a><br>
<a class="moz-txt-link-freetext" href="http://lists.osgeo.org/mailman/listinfo/mapserver-users">http://lists.osgeo.org/mailman/listinfo/mapserver-users</a><br>
</div>
</blockquote>
</div>
<br>
</blockquote>
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