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20021107: 20021107: AWIPS Grid 220.

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  • Subject: 20021107: 20021107: AWIPS Grid 220.
  • Date: Fri, 08 Nov 2002 14:33:16 -0700
Stonie,

I looked at the grid 220 in both GEMPAK and McIDAS. Both
compute the point the same way- which makes me wonder if the
interpretation of the +j direction scan flag is being
interpreted corectly.

Steve Chiswell


>From: "Stonie R. Cooper" <address@hidden>
>Organization: Planetary Data, Incorporated
>Keywords: 200211071907.gA7J76X04924

>Steve,
>
>Thanks!  Also - completely off subject - I have a patch for the netcdf build 
>in GEMPAK when compiled with gcc 3.2.  It's an extension of a patch that I 
>found in the netcdf group that just didn't quite make it.  Let me know if you 
>need it, and I'll send it on.
>
>Stonie
>p.s. 5.6.i - when?  Early Winter Holiday present?
>
>> Stonie,
>>
>> The A220 grid is supposed to have corners (as defined in
>> $GEMTBL/grid/grdnav.tbl and ncep's grib document) of:
>> -36.899;139.806   -31.850;-31.899
>>
>> I wrote dcgrib/dcgrib2 to always use the GDS if present, otherwise to look
>> up the navigation in the grdnav.tbl file. Looking at the gdinfo
>> output, it appears that the corners are being computed as:
>>    -36.87;139.81 24.47;142.77
>>
>> so, the GEMPAK grid file is being created with the wrong navigation.
>> The Upper Right (UR) corner point is incorrect. Probably a small bug in the
>> southern hemisphere computation of gds.latur/gds.lonur in gbpolr.c
>> or the angle/poinint of projection flags are not correctly set from the
>> grib.
>>
>> I'll have to look at it for 5.6.i. You might try nagrib with
>> cpyfil=#220.
>-- 
>Stonie R. Cooper
>Planetary Data, Incorporated
>ph. (402) 782-6611
>