calculations with "undefined" variables...

[Jamie Scott]

Chuck,

I get a similar behavior when scaling an undef value, but the new
-9.99e+33
value is still considered undef :

ga-> d mld/100
Data Type = grid
Dimensions = -1 -1
I Dimension = -999 to -999
J Dimension = -999 to -999
Sizes = 1 1 1
Undef value = -9.99e+33
Undef count = 1  Valid count = 0
Min, Max = -9.99e+33 -9.99e+33
ga-> d mld
Data Type = grid
Dimensions = -1 -1
I Dimension = -999 to -999
J Dimension = -999 to -999
Sizes = 1 1 1
Undef value = 32767
Undef count = 1  Valid count = 0
Min, Max = 32767 32767
ga->

-Jamie

On Feb 7, 2006, at 1:04 PM, Charles Seman wrote:

> Hi,
>
> Here are some results from a recent GrADS session...
>
> -------
>
> Grid Analysis and Display System (GrADS) Version 1.9b4
> Copyright (c) 1988-2005 by Brian Doty and IGES
> Center for Ocean-Land-Atmosphere Studies (COLA)
> Institute for Global Environment and Society (IGES)
> GrADS comes with ABSOLUTELY NO WARRANTY
> See file COPYRIGHT for more information
>
> Config: v1.9b4 32-bit little-endian readline sdf/xdf netcdf lats
> printim
>
> ...
>
> ga-> set gxout print
> ga-> set z 1
> LEV set to 0.035 0.035
> ...
> ga-> set x 1
> LON set to 167.113 167.113
> ga-> set y 1
> LAT set to 8.31355 8.31355
> ga-> d pp
> Printing Grid -- 1 Values -- Undef = -9999.9
> 100603
> ga-> d pp_dcreg
> Printing Grid -- 1 Values -- Undef = -9999.9
> -9999.9
> ga-> define ppb = aave(pp_dcreg,x=1,x=64,y=1,y=64)
> Define memory allocation size = 4 bytes
> ga-> d ppb
> Printing Grid -- 1 Values -- Undef = -9999.9
> -9999.9
> ga-> define ppb = aave(pp_dcreg,x=1,x=64,y=1,y=64)/100
> Define memory allocation size = 4 bytes
> Name already DEFINEd:  ppb.   Will be deleted and replaced.
> ga-> d ppb
> Printing Grid -- 1 Values -- Undef = -9.99e+33
> -9.99e+33
> ga-> d pp_dcreg/100
> Printing Grid -- 1 Values -- Undef = -9.99e+33
> -9.99e+33
>
> -------
>
> Is it true that GrADS always assigns -9.99e+33 to the result of
> scaling
> an "undef" value?
>
> Thanks,
> Chuck
>
> --
>
> ********************************************************************
> Charles Seman                                charles.seman at noaa.gov
> U.S. Department of Commerce / NOAA / OAR
> Geophysical Fluid Dynamics Laboratory         voice: (609) 452-6547
> 201 Forrestal Road                              fax: (609) 987-5063
> Princeton, NJ  08540-6649            http://www.gfdl.noaa.gov/~cjs/
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>
> "The contents of this message are mine personally and do not reflect
> any position of the Government or NOAA."