[ncl-talk] Raster image discrepancies between versions 6.1.2 and 6.2.x

[Andrea Allan]

Hello,

I am currently struggling with trying to diagnose small, but very
noticeable differences between raster images (png workstation) created in NCL
6.1.2 and the newest version 6.2.1, using the exact same code and data
files in both cases.  Large-scale patterns in the data are consistent;
however, something has changed between the two versions of NCL that make
the data shift ever so slightly (see attached images).

I've perused all the changes made in the the new version of NCL, and while
it is hard to pinpoint the problem, could this be related to the change in
how transparency is handled in raster contouring, or the raster contouring
method itself?  Searching the ncl-talk archives, I came across this
statement from another raster image-related problem:

"I think the problem is that the old workstation types do not understand
transparency in colors."

I have experimented with res at cnMissingValFillColor to no avail.  We have
also looked at data resolution vs. screen resolution, and while that makes
a difference within the figure, it does not solve the discrepancy between
versions.  Any insight regarding this issue is greatly appreciated.

Andrea


~~~
*Andrea M. Allan*
Postdoctoral Research Associate
College of Earth, Ocean, and Atmospheric Sciences
Oregon State University
112 Burt Hall
541-737-3427
aallan at coas.oregonstate.edu
~~~
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