comp.lang.idl-pvwave archive: archive » Re: GRIB data question

Home » Public Forums » archive » Re: GRIB data question

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: GRIB data question [message #78335 is a reply to message #78334]

Thu, 10 November 2011 09:22

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

Fabzou writes:

>
> On 11/10/2011 05:41 PM, David Fanning wrote:
>> Normally, if you work with map projection software at all,
>> you think of the first row and first column as being
>> located in the upper-left corner of the image data.
>> This is how ENVI, and GeoTiff files, and any netCDF
>> file I have ever worked with think.
>
> Some ncdf files are not like this, e.g. TRMM files, or output files from
> the community model WRF (which uses meteorological data in GRIB format
> as input).
>
> I don't know about GRIB files in general, though.

I found this piece of documentation. If you read the
section entitled The Solution - Part 1, toward the
end of the section, you find that the GRIB data has
a grid that goes from 90 to -90 in lat and 0 to 360
in lon, and he indicates the (1,1) point is at 90
deg N and 0 deg E. This indicates to me that the
convention is the upper-left convention, which is
(honestly) what I would expect.

http://www.iges.org/grads/gadoc/grib2.html

I see in the GRIB documentation itself that you are
encouraged to write the latitude and longitude of
not just the first grid cell, but the last grid cell,
too, which might remove this ambiguity. But, the data
that Mark provided (which he got from a NOAA source)
doesn't seem to follow this sensible convention,
either. :-(

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

Report message to a moderator

[Message index]

		Re: GRIB data question By: David Fanning on Fri, 11 November 2011 06:45
		Re: GRIB data question By: Kenneth P. Bowman on Fri, 11 November 2011 06:04
		Re: GRIB data question By: Kenneth P. Bowman on Fri, 11 November 2011 05:55
		Re: GRIB data question By: David Fanning on Thu, 10 November 2011 15:08
		Re: GRIB data question By: Kenneth P. Bowman on Thu, 10 November 2011 14:40
		Re: GRIB data question By: David Fanning on Thu, 10 November 2011 11:25
		Re: GRIB data question By: David Fanning on Thu, 10 November 2011 11:16
		Re: GRIB data question By: Kenneth P. Bowman on Thu, 10 November 2011 10:56
		Re: GRIB data question By: David Fanning on Thu, 10 November 2011 09:22
		Re: GRIB data question By: Fabzou on Thu, 10 November 2011 08:54

Previous Topic:	changing the content of a NCDF file
Next Topic:	Re: changing the content of a NCDF file

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 19:31:04 PDT 2025

Total time taken to generate the page: 0.00520 seconds