| Map_image questions [message #1344] |
Fri, 27 August 1993 10:37  |
doetzl
Messages: 4
Registered: January 1993
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Junior Member |
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I have a question concerning the Idl routine map_image. I have an image
of a 2d field, however the data is valid only over continents, and not
the sea. The data values for points over the sea are there they are
just not valid and are not flagged with any convenient missing data
flag. When I use map_image to warp this image onto a specific map
projection the bad sea values are interpolated with the good continental
values thus causing the values on the continental outlines to be
compromised. Is there a way around this? Does anyone have a map_image
like routine that will only interpolate a selected range of valid data
values? Is something like this possible/easy to write?
I'm open for suggestions.
Thanks
--Joe
|| Joe Doetzl | Climate Modeling Section ||
|| doetzl@pendragon.cgd.ucar.edu | National Center for Atmospheric Research ||
|| doetzl@ncar.ucar.edu | Boulder, Colorado (303) 497-1319 ||
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| Re: map_image [message #1912 is a reply to message #1344] |
Fri, 08 April 1994 00:47  |
stl
Messages: 70
Registered: February 1994
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Member |
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In article <2o1kru$okb@paperboy.gsfc.nasa.gov> fisher@echo.gsfc.nasa.gov (Brad L. Fisher) writes:
> ............................................ My question then is how do
> I get map_image to return the image with the map overlayed. Any help would
> be greatly appreciated.
hello,
well, as you realized, map_image just returns the image that can now
be displayed over your map (created with map_set).
First, create your map via map_set, creating continents, etc to your
liking. Then call map_image like the following:
wrapped_image = map_image(image,startx,starty,latmin = latmin,
latmax=latmax,lonmin=longmin, lonmax=longmax)
then to display this on top of your map, do the following:
tv,wrapped_image,startx,starty
then you may need (want) to redraw the grids or continents with map_grid
and map_continents.
Oh, just noticed almost this exact example is in the reference guide
under map_image.
If your question is how do you get the entire new image and the map into
one image, read it back from the screen with tvrd once you put it all
together. Or if you don't ever want it to appear on the screen, use a
pixmap instead of a visible window.
hope this helps, good luck,
-stephen
--
Stephen C Strebel / SKI TO DIE
stl@maz.sma.ch / and
Swiss Meteorological Institute, Zuerich / LIVE TO TELL ABOUT IT
01 256 93 85 / (and pray for snow)
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