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Re: [GEMPAK #YCE-717567]: Question on GDPLOT (well, 2)



Unidata GEMPAK Support wrote:
Our grid is an LCC 60/-101/30 grid with corners (via GAREA) as:
GAREA 23.84;-106.81;37.36;-84.1

I'd have thought that we'd have some blank (or black) data in this
region but the image we're seeing isn't consistent with the reprojection
geometry I'd expected for a CED result, so either I'm coffee-deprived or
confused. I'll look at interpolating using GDDIAG. Thanks.


Gerry,

Yes, you image does have blank area on the east side, the curving up and to
the right boundary. This is what you would expect by projecting an
LCC grid using a CED defined domain. Note that the grid projection is
independent of the GAREA and PROJ you chose to define the display area
in gdplot2. As I had said before, without knowing what your
grid or domain was and no map on your plot, I couldn't provide much info.
Looking at your grid definition of LCC/60;-101;30, if your GRDAREA is
23.84;-106.81;37.36;-84.1
Then you can plot this in gpmap to see your eastern boundary will be
a line from the yucatan north to AL/GA, TN, KY.

Now plotting the same GAREA with CED projection will have an eastern boundary 
from Western CUBA,
north to Gentral GA and NC/TN. As a result, a display with that CED should have 
the plotted grid
data showing a blank area from Yucatan to Cuba, and curving NE to the upper 
right corner
of the plot.

Short answer: I was confused. Thanks for the explanation. It makes a bit more sense now. I'll play some more and see if I need to invoke gddiag.

Thanks again!
gerry
--
Gerry Creager -- address@hidden
Texas Mesonet -- AATLT, Texas A&M University        
Cell: 979.229.5301 Office: 979.458.4020  FAX 979.862.3983
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