[ncl-talk] PNG image quality in v6.2.0 and later

[Russ Schumacher]

Hello,

I had been using NCL v6.1.2 for a long time and recently needed to upgrade on a machine and installed v6.3.0. I’m having an issue where PNG images don’t look nearly as good in the more recent versions of NCL.  I see that there were many changes to contouring made after v6.2.0 so it’s possible that there are some settings I need to change, and would appreciate some insight into what those are.  As an example of the issue, I’ve attached a couple images here, made with identical code, with v6.1.2 (first image) and v6.3.0 (second image).  As you can see, in the v6.1.2 version the edges of the contours are crisp and the map looks ‘pretty’ whereas in the v6.3.0 version nothing is nearly as sharp.  

I can pass along the specific code if need be (basic parameters are that I’m using gsn_csm_contour_map to make the contour plot; writing to a “png” workstation) but I’m guessing there are just a couple settings that I’m missing that are now ‘best practice’ for the PNG driver.   I thought it was probably just an issue with my computer, but I reproduced the same behavior on yellowstone (which nicely has many different NCL versions installed!) and the switch happens at v6.2.0.  I tried changing the “wkAntiAlias” settings but that didn’t help.  Any help you could offer would be much appreciated!

Thanks,
Russ








--
Russ S. Schumacher
Associate Professor
Department of Atmospheric Science
Colorado State University
e-mail: russ.schumacher at colostate.edu <mailto:russ.schumacher at colostate.edu>
phone: 970.491.8084
web: http://www.atmos.colostate.edu/faculty/schumacher.php <http://www.atmos.colostate.edu/faculty/schumacher.php>






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