[GRASS-user] MODIS HDF conversion in TIF tool.

[Nikos Alexandris]

Hello Ivan.

Well,

thank you for all of the information.

If it is really not for free, then it does not satisfy my needs. I will have
to find an alternative way.

But I didn't find any statement anywhere in the official page about
non-free. I want to complete a work using exclusively free tools (and if
possible open-source as well).


I understand that it is not open-source which is different from cost-free.
Anyway, while contacting with ... I got his response (in which he offers to
give the code if needed). This is why I considered that it could be
interesting for programmers maybe. Here is his reply:

"Nikos, 

It looks like that we have a bug in the grid stitching code (I was able to
duplicate your result). We will fix it as soon as possible (if you really
need the grid stitching code please let me know). Since you are converting
only one file, you do not need grid stitching code. Just use conversion GUI
(the one that appears when you open HEG. Do not select Stitch/Subset from
Tool Menu). I tried the conversion and it worked fine for TM projection. One
problem that I noticed was that in this projection the output file (the
grid) for the product you are using is huge. Although the conversion
produced the output HDF file for me, I was not able to open it with HDFView
because of its size. Once I made another conversion putting (5000, 5000)
meters for the pixel size (about 10 times the actual pixel size in X-Y
directions), then the size of the file was suitable for opening by HDFView.
You may not need to adjust your pixel size since you want tif output. 

-Abe 


Abe Taaheri, Ph. D.
Sr. Scientist/Software Engineer
Raytheon Information Systems
NASA EMD Program
1616 McCormick Drive
Upper Marlboro, MD 20774
Work: (301) 925-0783
Abe_Taaheri at raytheon.com"

...and they even mention grass as an option to use for GeoTIFF files. [
http://newsroom.gsfc.nasa.gov/sdptoolkit/HEG/HEGFAQ_Tools.html#question1 ]

Cheers,

Nikos.

Ivan Shmakov-3 wrote:
> 
>>>>>> "NA" == Nikos Alexandris <nikos.alexandris at felis.uni-freiburg.de>
>>>>>> writes:
> 
>  NA> There is a handy tool called HEG [HDF-EOS To GeoTIFF Conversion
>  NA> Tool] with which one can convert HDF files into .tif.
> 
>         Please note that it process only HDF-EOS files, and not
>         arbitrary HDF's.
> 
>  NA> It can be used to create subsets as well. The tool has two modes:
>  NA> a. stitching/subset modus and b. conversion modus.
> 
>  NA> It is written in C and Java (for the GUI).
> 
>  NA> Could it be useful for GRASS?
> 
>         Yes.  However, please note that it's not free software (as
>         defined by, e. g., DFSG [1]) nor open source (as defined by OSD
>         [2].)
> 
>         My personal opinion is that it's a bit brain-damaged as well.
>         Given that PROJ.4 [3] is free software, implementing a viable
>         free software / open source alternative will probably take a
>         developer-month or so (and I've some simple code which works for
>         me on AIRS data, which aren't supported by HEG quite well.)
>         (Although I'm not sure about the exact HDF-EOS libraries
>         license.)
> 
>  NA> Is there any plan to implement a handy tool to import MODIS
>  NA> imagery?
> 
>         Well, I've an Awk script or two to automagically convert
>         `hegtool' output (.hdr) into a control file for swtif.
> 
>  NA> * I already read almost all mails in the list referering to the HDF
>  NA> import problematic.
> 
>  NA> link: http://newsroom.gsfc.nasa.gov/sdptoolkit/HEG/HEGHome.html .
> 
> [...]
> 
> [1] http://www.debian.org/social_contract
> [2] http://www.opensource.org/docs/osd
> [3] http://proj.maptools.org/
> 
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> grassuser mailing list
> grassuser at grass.itc.it
> http://grass.itc.it/mailman/listinfo/grassuser
> 
> 

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