Out of buffer space

[Jennifer Adams]

On May 14, 2009, at 2:50 PM, Ramon Solano wrote:

> Dear users,
>
> I am working with a pretty large dataset (5400 col x 3600 row), and
> by now
> reducing the spatial resolution is not a possibility.
>
> Two questions:
>
> 1. When I try to diplay one image, GrADS notifies that an "Out of
> buffer space"
> error happened, and even though the image is fully diplayed on the
> screen, the
> hard copy (a .png file)  is truncated (I got only about 90% of the
> image). Is
> there a way to increase the buffer size or another way to cope with
> this
> problem? I'd be willing to try even a source compilation if necessary.
When you invoke GrADS, use the -m NNN option.
This sets metafile buffer size to NNN, which must be an integer.
Default value is 1000000.

>
> 2. For high resolution datasets showed on screen or printed at large
> scale, what
> is the resampling technique used by GrADS to select the final output
> for a given
> pixel (NN, BIL, etc)? I.e., a pixel on screen or on an image has
> several pixels
> underneath, but only one value will be shown. Is there a way to
> control this
> resampling?
All of that is handled by the gd library. I have no idea what the
algorithm is (might be in the library's documentation), but I do know
that GrADS does not exploit the anti-aliasing option that is available
in the newer version of the gd library. (Brian discovered it didn't
work with line thicknesses, so he did not enable it.) I made this tiny
plot and it has white pixels where text used to be:




>
>
> Thanks in advance,
> Ramon.
> --
> Ramon Solano, Research Specialist
> Terrestrial Biophysics and Remote Sensing Lab.
> Dept. of Soil, Water and Environmental Sciences
> University of Arizona

--
Jennifer M. Adams
IGES/COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705
jma at cola.iges.org



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