Luigi Romolo wrote:
> Has anyone ever used NCL for the purposes of creating shaded relief
> maps? What I would like to do is create a shaded relief map for various
> US States...similar to the ones posted on
> http://fermi.jhuapl.edu/states/states.html. In addition, I would like
> to know if anyone has created a shaded relief map with a contour layer
> over it (say monthly precip for example). Any direction towards a
> solution to this agenda would be greatly appreciated.
I used NCL to read the USGS DEM 30-second data and create a
grayscale terrain map over which I plot various data (research
aircraft data mostly). View an example image here (near the
middle of the page):
http://www.rap.ucar.edu/~gthompsn/workshop2004/
My code is pretty crude and isn't very modular but you're welcome
to it. Primarily you want to contour terrain altitude using a
raster fill using these specific parameters:
"cnRasterModeOn" : True
"cnRasterSmoothingOn" : False
"cnLinesOn" : False
"cnLineLabelsOn" : False
My code does not create the false sun angle shadow effect that
can be seen at these two URLs (these latter images were created
by my coworker using the GD image library by Thomas Boutel).
It could all be done within NCL though with the right geometry
to fake a sun angle.
http://www.rap.ucar.edu/~gthompsn/2001Oct09/20011009_220104_BREF1color.png
http://www.rap.ucar.edu/~gthompsn/2001Oct09/20011009_220104_BREF1gray.png
-- +--------------------------------------------------------------+ | Greg Thompson http://www.rap.ucar.edu/~gthompsn/ | | Research Applications Program | | (303) 497-2805 National Center for Atmospheric Research | | (fax) -8401 P.O. Box 3000 Boulder, CO 80307-3000 | +--------------------------------------------------------------+ _______________________________________________ ncl-talk mailing list ncl-talk@ucar.edu http://mailman.ucar.edu/mailman/listinfo/ncl-talk
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