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[GEMPAK #ZIZ-192685]: Re: 20060123: bugs in gdprof and gdpoint

>To be honest, I am still puzzled by your response to this issue, which
>I finally have time to study once again. My basic assertion is that
>GDPROF and GDPOINT give wrong answers for wind speeds and directions
>because they do not use interpolated wind components (even though
>GDPROF will display them for you).

David,

The key here is, as you noted, that the GFUNC scalar calculation
involving a vector has correct values at the grid points, but not at the 
interpolated gpoint location where the resultant value is interrpolated from 
the surrounding
grid point values after the scalar field is calculated, rather than 
interpolating
the components individually to the desired point and then performing the 
calculation
of the scalar quantity.

As I noted previously, one solution is to interpolate the grid points first 
which can now be 
done through the new grid library interface.

I have reposted the 5.9.1 distribution tarfiles, both source and binary 
versions,
which implement a method whereby the grid is translated so that the GPOINT 
location
is colocated with the grid point- so that the component values are interpolated
to the location first, and then the scalar value is obtained. These tar files 
will have a 
posting data of March 9 on the web portal.

Steve Chiswell
Unidata User Support

Ticket Details
===================
Ticket ID: ZIZ-192685
Department: Support GEMPAK
Priority: Urgent
Status: Closed