[gradsusr] Negative Longitude of -360 in xdef of ctl file

Raphael Ranieri raphaelcr93 at hotmail.com
Tue Aug 11 17:07:36 EDT 2020


Hello All,

I'm trying to use some files of a Brazillian institute of meteorology and I'm facing a problem with the longitude values.

They used grads to create a ctl file that can be accessed in this FTP from the institution:
http://ftp.cptec.inpe.br/modelos/tempo/BAM/TQ0666L064/recortes/regioes/2020/07/29/00/BAM_CO_2020072900.ctl

[cid:78306f6d-96b0-45b9-b892-7fcc822a714b]

Here we can see that they are using a linear mapping for xdef with a 0.18 step starting from a longitude of -360 degrees according to GrADs docs:
http://cola.gmu.edu/grads/gadoc/descriptorfile.html#XDEF


Since in our case we need the actual longitude and latitude of a point, when we try to read this file we receive longitudes of 360 for example, which do not correspond to any existing longitude.

We are not using Grads to open the file, we are using pygrib ... to use it in a python program.

Since this ctl file is generated by grads we tought you guys could help.

Do you know why the longitude is starting at -360?

Thanks in advance!

Raphael Ranieri
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gradsusr.org/pipermail/gradsusr/attachments/20200811/69371c5f/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Captura de Tela 2020-07-29 a?s 8.38.13 PM.png
Type: image/png
Size: 180037 bytes
Desc: Captura de Tela 2020-07-29 a?s 8.38.13 PM.png
URL: <http://gradsusr.org/pipermail/gradsusr/attachments/20200811/69371c5f/attachment-0001.png>


More information about the gradsusr mailing list