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20040224: Hyperslab I/O of Varying Size: use of IMAP argument

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  • Subject: 20040224: Hyperslab I/O of Varying Size: use of IMAP argument
  • Date: Tue, 24 Feb 2004 11:27:48 -0700
Ben,

>Date: Tue, 24 Feb 2004 11:58:20 -0600
>From: Ben Howell <address@hidden>
>Organization: University of Wisconsin, Madison/SSEC
>To: Steve Emmerson <address@hidden>
>Subject: Re: 20040224: Hyperslab I/O of Varying Size: use of IMAP argument
> Keywords: 200402181846.i1IIkk2N001457

The above message contained the following:

> Attached is the file "GOES1993nc.cdl", written by "ncdump -h".
> The 3-d variable "data" is the source of "btemp1".
...


> netcdf GOES1993 {
> dimensions:
>       lines = 250 ;
>       elems = 600 ;
>       bands = 1 ;
...
> variables:
>       float data(bands, lines, elems) ;
>               data:long_name = "data" ;
>               data:type = "VISR" ;
>               data:units = "degrees K" ;
>       float latitude(lines, elems) ;
>               latitude:long_name = "latitude" ;
>               latitude:units = "degrees" ;
>       float longitude(lines, elems) ;
>               longitude:long_name = "longitude" ;
>               longitude:units = "degrees" ;
> }

Use the following code to read the above latitudes, longitudes, and
brightness temperatures into multi-dimensional, statically-sized arrays:

    parameter (maxelems=1200, maxlines=500)
    real*4 btemp1(maxelems, maxlines)
    real*4 slat(maxelems, maxlines)
    real*4 slon(maxelems, maxlines)
    integer idcdf, idlon, idlat, idbtemp
    integer start(3), count(3), stride(3), imap(3)
    integer idlines, idelems, nlines, nelems
    ...

    nf_inq_dimid(idcdf, 'lines', idlines)
    nf_inq_dimid(idcdf, 'elems', idelems)
    nf_inq_dimlen(idcdf, idlines, nlines)
    nf_inq_dimlen(idcdf, idelems, nelems)
    start(1) = 1
    start(2) = 1
    count(1) = nelems
    count(2) = nlines
    stride(1) = 1
    stride(2) = 1
    imap(1) = 1
    imap(2) = maxelems
    nf_get_varm_real(idcdf, idlat, start, count, stride, imap, slat)
    nf_get_varm_real(idcdf, idlon, start, count, stride, imap, slon)
    start(3) = 1
    count(3) = 1
    stride(3) = 1
    imap(3) = maxelems * maxlines
    nf_get_varm_real(idcdf, idbtemp, start, count, stride, imap, btemp1)

Look this over.  Contact me if you have any questions.

Regards,
Steve Emmerson