Re: 20051219: IDV - NetCDF data files with curvilinear coordinates / CF convention

Unidata Support wrote:
> > To: address@hidden
> > From: "Stuart Wier" <address@hidden>
> > Subject: IDV - NetCDF data files with curvilinear coordinates / CF convention
> > Organization: UCAR/Unidata
> > Keywords: 200512191651.jBJGpYJU012442
>
>
> Institution: unavco
> Package Version: 1.2
> Operating System: linux
> Hardware Information: the ususal
> Inquiry: I have a GEON IDV user who wants to see seismic tomography (seismic 
> velocity values in 3D) from a 3D volume data grid. His  data file is a 
> collection of what are unique longitude-latitude pairs for each grid point at 
> each depth:
>
>   long    lat     depth Pv
>
> > 138.717 37.1541 9 5.8325
> > 138.773 37.1542 9 5.9639
> > 138.829 37.1543 9 6.1133
> > 138.886 37.1543 9 6.1892
> > 138.942 37.1543 9 6.0828
> > 138.998 37.1543 9 5.9052
> > 139.054 37.1543 9 5.8052
> > 139.111 37.1543 9 5.8607
> > 139.167 37.1542 9 5.9771
> > 139.223 37.1541 9 6.0249
>
>
> (there are 17 megabytes of this, spanning about 100 depth levels. The depths 
> are regular: identical 2D grids for each depth.)
>
> I suspect that this is a regular rectangular x-y grid mapped onto longitude-latitude locations.  
>
> I recall this can be handled by the CF convention if enough is known about the 
> projection, right?  What exactly is required in the NetCDF file, and is there 
> an example of a NetCDF file to use as a guide?

Yes, he can use the CF conventions. Just have a 2D lat and a 2D lon variable, 
see section 5.6 of CF manual.

Basically you have:

 float dataVariable(x,y,z);
   :coordinates="lat lon";
 float lat(x,y); 
 float lon(x,y); 
 float z(z); 

If its really from a projection (and its one we can deal with) then thats a 
more efficient way to go.

> Stu
>
>
>
> --
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