Does Grads support 5D data?

[Wenli Yang]

Jennifer,

Thanks for you prompt response.  Will check v1.9.  All our dimensions are orthogonal (i.e., orbit/time/pressure not varying with y/x; orbit/band not varying with t/z/y/x) and thus v1.9 might work.

Wenli

----- Original Message -----
From: Jennifer Adams <jma at COLA.IGES.ORG>
Date: Monday, December 10, 2007 2:57 pm
Subject: Re: Does Grads support 5D data?

>
> On Dec 10, 2007, at 12:19 PM, Wenli Yang wrote:
>
> > Hello,
> >
> > Does Grads support 5D data?  I saw Jennifer and some other people
> > were discussing 5D data in grads about a year ago (http://
> > www.cgd.ucar.edu/pipermail/cf-metadata/2006/001207.html).
> The support for 5D grids is in version 2.0, soon to be available as
> an alpha release.
>
> > We produced some 5D data in CF-netCDF in the following dimension
> > order: Orbit * Time * Pressure * Latitude * Longitude
> > where the orbit dimension records number of satellite orbits the
> > data may contain, ranging from 1 to 14, and Time and Pressure are
> > mostly just one, such as the following: 10 * 1 * 1 * 180 * 360.
> > We correctly named T/Z/Y/X for the last for dimensions and didn't
> > set the "axis" attribute to the first "orbit" dimension.  We seem
> > not be able to display such data in Grads.  I am not sure if it's
> > our data problem or Grads still does not support 5D.
> You could look at this data with version 1.9 by putting non-negative
> integers array indices in the units field of the variable
> declaration. From the docs:
>
> If your data file contains a variable that also varies in a non-
> world-
> coordinate dimension (e.g. histogram interval, spectral band,
> ensemble number) then you can put a non-negative integer in the list
> of varying dimensions that will become the array index of the extra
> dimension. For example:
>
>       VAR=>hist0   0   0,y,x   First historgram interval for VAR
>       VAR=>hist1   0   1,y,x   Second historgram interval for VAR
>       VAR=>hist2   0   2,y,x   Third histogram interval for VAR
>
> I have not tested this option with 5D data, I don't think it will
> work if VAR also varies in Z and T.
>
>
> >
> > A more general question is perhaps: does Grads support high
> > dimensional data in the following form:
> >   D1 * D2 * ... Dn * T * Z * Y * X
> GrADS has a 4D (soon to be 5D) environment for grids -- it won't read
> data with more dimensions than that. HDF is a more general format,
> doesn't limit the number of dimensions an array can have. GrADS can
> handle some, but not all, HDF gridded files.
>
> >
> > I use HDFview to display multidimensional HDF data.  HDFView allows
> > users to specify which dimension is horizontal, vertical, etc.  Can
> > this also be done in Grads?
> >
> > Many Thanks,
> >
> > Wenli Yang
>
> --
> Jennifer M. Adams
> IGES/COLA
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705
> jma at cola.iges.org
>
>
>
>