[CF-metadata] Grid mapping information

From: cristina.tronconi at artov.isac.cnr.it <cristina.tronconi>
Date: Fri, 16 Jul 2010 10:12:47 +0200

Helloevertybody,
I have a netcdf file (chlorophyll gridded satellite daily map) in
which I have my variable chl(tim,lat,lon), then the vector of regular
lat and a vector for
regular lon.

My grid mapping is Equidistant Cylindrical. SO in the nc I set as
GLOBAL ATTRIBUTE
----------------------------------
      attname=Conventions
      value=CF-1.4

      attname=grid_mapping
      value=Cylindrical
------------------------------------
Some question:
1) A collegue of mine told me that for CF 1.4 the grid_mapping is no more
a global attribute but it is a variable attribute named as
"grid_mapping_name".

BUT I run the CF checker for 1.4 on my file and everything is ok!!!!

SO: Is it still correct /with cf 1.4) to set a global attribute as
"grid_mapping" in the case (obviuosly) all the variables use the same
grid_mapping? or must I put the same information as variable
attribute? in this case, how?

2) are "Equidistant Cylindrical" and "Cylindrical" still CF valid values for
grid_mapping (or grid_mapping name)? I found only "Equirectangular" In
the "Content Standard for Digital Geospatial Metadata. Federal
Geographic Data Committee, FGDC-STD-001-1998" document mentioned in
the Appendix F. Grid Mappings of CF 1.4.

thanks in advanced
Cristina

-------------------------------------------------------------------
Cristina Tronconi
Istituto di Scienze dell'Atmosfera e del Clima - sezione di Roma
Consiglio Nazionale delle Ricerche
Via Fosso del Cavaliere 100
00133 Roma, Italy
Tel: +39 06 49934342
cell: '39 349 1242954
Fax: +39 06 20660291
e-mail: cristina.tronconi at artov.isac.cnr.it
Received on Fri Jul 16 2010 - 02:12:47 BST