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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
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Hi Evan,In GDDIAG, try setting the packing variable "GPACK" to "NONE". The default, if "GPACK" is set to <blank> is to use "GRIB/16" packing. I think you may have unconvered a bug in the packing process which is not treating a grid whose points are all set equal to "RMISSD" properly.
--Kevin ______________________________________________________________________ Kevin Tyle, Systems Administrator ********************** Dept. of Atmospheric & Environmental Sciences ktyle@xxxxxxxxxxxxxxxx University at Albany, ES-235 518-442-4578 (voice) 1400 Washington Avenue 518-442-5825 (fax) Albany, NY 12222 ********************** ______________________________________________________________________ On 10/08/2010 12:20 PM, Evan Lowery wrote:
Hello all,I've found a possible bug (or user error) with GDDIAG and the MASK grid function, but wanted to check with everyone here before sending out an official support request.Within a GEMPAK grid file (test.grd), I have a temperature field (TEMPA) which needs to be masked to only show values between a certain temperature range (>=80F). I run this process daily, and have never had a problem up until this point. When NO temperatures in TEMPA are >=80F, the MASK function generates an erroneously large number rather than -9999.00 (RMISSD).Dataset: test.grd gdlist GDATTIM=101007/0000F001 GLEVEL=0 GVCORD=NONE GFUNC=TEMPA Using GDLIST (tempa.dat) I see that TEMPA: MINIMUM AND MAXIMUM VALUES 1.03 60.00 Goal: only keep temperatures >=80F gddiag GDATTIM=101007/0000F001 GLEVEL=0 GVCORD=NONE GFUNC=MASK(TEMPA,SGE(TEMPA,80)) GRDNAM=TEMPB GRDTYP=S GPACK= GRDHDR= PROJ= GRDAREA= KXKY= MAXGRD= CPYFIL= ANLYSS= Using GDLIST (tempb.dat) I see that TEMPB:MINIMUM AND MAXIMUM VALUES9999999848243207295109594873856.009999999848243207295109594873856.00I would expect all TEMPB values to be -9999.00 (RMISSD) since no temperatures are greater than 80F, but instead it blows up and returns a very large value.http://www.unidata.ucar.edu/cgi-bin/gempak/manual/apxB_index MASK Masking function MASK (S1, S2) = RMISSD IF S2 = RMISSD = S1 otherwiseIn this example TEMPA had no values >=80F, but my csh scripts are constantly mining through temperature grids, and "usually" there are values >=80F.Has anyone ever experienced this type of result? If yes, do you know a work around to get the grid (TEMPB) with all values = -9999.00 (RMISSD) rather than erroneously large values?Regards, Evan Lowery _______________________________________________ gembud mailing list gembud@xxxxxxxxxxxxxxxx For list information or to unsubscribe, visit: http://www.unidata.ucar.edu/mailing_lists/
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