[gradsusr] geotiff files

[Michael Mase]

Sure, here is some documentation also:

www.cpc.ncep.noaa.gov/products/wesley/wgrib2/new_grid.html

Installing wgrib2 can be kind of a pain because you need fortran and gcc
pointed correctly, but once you get it set up, it's extremely useful. GrADS
might come with it, I'm not sure though.

My quick steps are:

-know the resolution of the product that you are working with
-know your starting and ending lat/lon

In the below example, I'm starting at a longitude of -145 and creating 760
points at a resolution of 0.125 degrees. Same goes for latitude, starting
at 15 degrees and going up 320 points at an interval of 0.125 degrees. This
will output a grib that is a lat/lon grid of 760x320 at a resolution of
0.125 degrees. This can also be used to interpolate the data to a finer
resolution if you prefer, but since you are using GrADS, I recommend simply
maintaining the original resolution and let GrADS handle the interpolation.

* wgrib2 input.grib2 -set_grib_type same -new_grid latlon -145.0:760:0.125
15.0:320:0.125 output.grib2*

Let me know if you have any questions.

Mike




On Fri, Jan 29, 2016 at 8:54 AM Andres Lighezzolo <
andreslighezzolo at gmail.com> wrote:

> Thanks Michael!, can you show me how you do it?
>
>
> 2016-01-28 11:59 GMT-03:00 Michael Mase <masester at gmail.com>:
>
>> Hm, that's a good question. I usually convert from a gaussian grid to a
>> lat lon grid with wgrib2, which seems to work very well.
>>
>> On Thu, Jan 28, 2016 at 9:57 AM Andres Lighezzolo <
>> andreslighezzolo at gmail.com> wrote:
>>
>>> Dear GRADS users,
>>>
>>> I usualy work with grb2 files from GFS model and using these in a
>>> geographical information system. I open and then transform the grb2 files
>>> in geotiff files with the sentence 'set gxout geotiff'. No problems with
>>> that, the file geottif is generated correctly.
>>>
>>> But now i'm working with CFSv2 files. When a try to transform these
>>> files to geotiff with the 'set gxout geotiff', the file is created but is
>>> not georeferenced.
>>>
>>> GFS files are in lat-lon grid:(1440 x 721)  defined as:
>>>
>>> ydef 721 linear -90.000000 0.25
>>>
>>> xdef 1440 linear 180.000000 0.250000
>>>
>>>
>>> and CFSv2 files are Gaussian grid: (384 x 190) defined as:
>>>
>>> xdef 384 linear 0.000000 0.9375
>>>
>>> ydef 190 levels
>>>
>>>  -89.277 -88.340 ........... 87.397  88.340  89.277
>>>
>>>
>>> Can Grads make geotiff with georeference when the ydef is defined by
>>> levels?
>>>
>>>
>>> Thanks in advance
>>>
>>>
>>> --
>>> Mgter. Andrés Lighezzolo
>>> Área/Departamento: Gerencia de Institucionales/Unidad Emergencias
>>> Nacionales y CAEARTE
>>> Sede CONAE Córdoba: Centro Espacial Teófilo Tabanera - Falda del Carmen.
>>> Teléfono 54-3547-400000 interno 1189
>>> Argentina
>>> http://meteo.caearte.conae.gov.ar/wrf
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>
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>
>
> --
> Mgter. Andrés Lighezzolo
> Área/Departamento: Gerencia de Institucionales/Unidad Emergencias
> Nacionales y CAEARTE
> Sede CONAE Córdoba: Centro Espacial Teófilo Tabanera - Falda del Carmen.
> Teléfono 54-3547-400000 interno 1189
> Argentina
> http://meteo.caearte.conae.gov.ar/wrf
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
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