[CF-metadata] longitude, latitude and compress

From: Jonathan Gregory <j.m.gregory>
Date: Wed, 5 Sep 2007 09:00:24 +0100

Dear Antonio

> 2. In my netCDF I have longitude and latitude as variables. Do you know if
> they can be declared 2D in the CF convention ? i.e.: can it be:
>
> float lon (lat,lon) and
> float lat (lat,lon)

Yes, they can be declared as 2D if lat and lon are not the 1D axes of the
data variable. In that case lat and lon should be named by the coordinates
attribute of the data variable, as described in CF 5.2. However, the 2D
coordinate variables should in this case *not* have the same name as the
1D dimensions e.g. not lon(lat,lon) (which doesn't really make sense) but
something like lon(y,x).

If you are compressing the x and y dimensions into a 1D index dimension,
as in CF 8.2, the lat and lon variables will become 1D as well, I suppose,
like the data variable.

Best wishes

Jonathan
Received on Wed Sep 05 2007 - 02:00:24 BST