.ctl for MODIS HDF file

[Hao He]

I put this in my .ctl file as an example:

set ^MOD06_L2.A2008094.0225.005.2008096042152.hdf
title MODIS Level 2 cloud product
undef -32768
xdef 270 linear 112.856 0.1201260
ydef 406 linear 29.1195 0.0525835
tdef 1 linear 02:25Z03APR2008 5MN
zdef 1 linear 1 1
dtype hdfsds
vars 3
Latitude=>scanlat 0 y,x Geodetic Latitude
Longitude=>scanlon 0 y,x Geodetic Longitude
Surface_Pressure=>sfcpres 0 y,x Surface Pressure
endvars

But I got this warning:

Scanning description file:  MOD06_L2.A2008094.0225.005.2008096042152.ctl
Open Error:  Data file type invalid
   --> The invalid description file record is:
   --> dtype hdfsds

I am confused about the data type. Not HDF-SDS?

Hao

|  Hao He                                       |
|  Graduate Assistant                           |
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|  Jull Hall lab (301)405-7625                  |
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|  Department of Atmospheric & Oceanic Science  |
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|  College Park, MD 20742                       |

On Mon, 19 Oct 2009, Jennifer Adams wrote:

> I can't allow misinformation to go out to the list uncorrected: GrADS
> can read any HDF file containing gridded fields.
> This particular HDF file contains swath data. It's gridded -- there
> are 406 cells in the along-swath direction, and 270 cells in the
> across-swath direction. GrADS will read this data, but only onto an
> abstract x,y grid. The lat/lon values of each grid point are read in
> as data variables. A full 'dtype hdfsds' descriptor file would include
> the following lines:
>
> xdef 270 linear 1 1
> ydef 406 linear 1 1
> tdef 1 linear ...
> ...
> vars 4
> Latitude=>scanlat 0  y,x  Geodetic Latitude
> Longitude=>scanlon 0 y,x Geodetic Longitude
> Scan_Start_Time=>scantime 0 y,x International Atomic Time at Start of
> Scan replicated across the Swath
> Surface_Temperature=>tsfc 0 y,x Surface_Temperature
> endvars
>
> You can add more variables, including some that have a Z axis,
> depending on what you'd like to look at in the file. The rest of the
> required descriptor file entries are discussed in the documentation
> page http://iges.org/grads/gadoc/SDFdescriptorfile.html
>
> --Jennifer
>
>
> On Oct 19, 2009, at 10:49 AM, Yan Libin wrote:
>> a ctl is not enough
>
> On Oct 19, 2009, at 10:49 AM, Jayakrishnan PR wrote:
>> ... we cannot open them through grads by writing a ctl file.
>
>
> On Oct 19, 2009, at 10:26 AM, Hao He wrote:
>
>> Hi,
>> I want to read MODIS HDF file by GrADS. Unfortunately both sdfopen
>> and
>> xdfopen do not work for me, so I need to write a complete .ctl file.
>> But
>
>> I am confused after reading the MODIS data set
>> (http://modis-atmos.gsfc.nasa.gov/MOD07_L2/format.html)
>
>> I am wondering if anyone has experience on it.
>> Thanks a lot!
>>
>> Hao