Using GrADS to open HDF-EOS

[Christopher Lynnes]

On Sep 23, 2009, at 12:59 PM, Mike Bosilovich wrote:

> It's not clear which data you are looking at, level 2 or level 3.  The
> descriptor file below I used to analyze the level 3 global 5km MODIS
> LST product.  I don't think level 2 is possible.
>
> When i've wanted to analyze the level 2 granules in grads, I had to
> first convert to a regular grid. I think HDFView will do that, but not
> in a batch way.
>
> I hope that someone has a better answer than mine!

I don't have any better news, but a little more detail.  The Cloudsat
and CALIPSO are both Level 1B or 2, meaning satellite swath / vertical
profile (not grid), and so are not well suited to GrADS, where the
"Gr" stands for "Grid" 8-).   There may be a way to define an X-Y grid
with X being along-track distance and Y the vertical height / pressure
level, but I admit that is beyond my ken.

Converting to NetCDF/CF-1, unfortunately, does not solve this. (Though
if you could properly convert to NetCDF/CF-1, the IDV tool could be
used instead; however the reformatting of the geolocation aspect is a
tricky thing.)

If you want to *visualize* Cloudsat or CALIPSO swath/profile data, you
can do that online at our A-Train Data Depot:
http://gdata1.sci.gsfc.nasa.gov/daac-bin/G3/gui.cgi?instance_id=atrain

Analysis and manipulation, alas, requires more work on your part...

>
> Mike
>
> DSET MOD11C1.A2001%m2%d2.004.hdf
> title MODIS Land Surface Temperature (LST) CMG v4
> DTYPE hdfsds
> OPTIONS yrev template
> unpack scale_factor add_offset
> undef 0 _FillValue
> XDEF 7200 linear -180 0.05
> YDEF 3600 linear  -90 0.05
> ZDEF 1 linear 1 1
> TDEF 115 linear 04jul2001 1dy
> VARS 6
> LST_Day_CMG=>LSTDay 0 y,x Daily daytime 3min CMG Land-surface Temp
> LST_Night_CMG=>LSTNite 0 y,x Daily nighttime 3min CMG Land-surface
> Temp
> QC_Day=>QCDay  0 y,x Quality control for daytime LST and emissivity
> QC_Night=>QCNite  0 y,x Quality control for nighttime LST and
> emissivity
> Day_view_time=>DayTime  0 y,x Time of daytime LST observation (UTC)
> Night_view_time=>NiteTime  0 y,x Time of nighttime LST observation
> (UTC)
> ENDVARS
>
>
> On Wed, Sep 23, 2009 at 1:18 AM, Aaron Pratt <aspratt2000 at yahoo.com>
> wrote:
>> Is there a way to use Windows-based GrADS (or GrADSnc, GrADS-DODS,
>> GrADS-HDF, etc) to open HDF-EOS files associated with MODIS,
>> CloudSat, and
>> CALIPSO? Or should they be converted into NetCDF files? Thanks in
>> advance
>> for any information that anyone has on this; it would be greatly
>> appreciated.
>>
>>
>>
>> Aaron

--
Christopher Lynnes             NASA/GSFC, Code 610.2
301-614-5185