Hi completely new to this, was wondering if anyone could point me to any links or documentation for a complete beginner or send me some sample scripts. Trying to use command line to create calibrated, terrain corrected geotiff’s from sentinel 1 a zipped data products.
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Note there is a short intro in the SNAP help system.
I agree that we urgently need such a beginners and expert guide: https://senbox.atlassian.net/browse/SNAP-306
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Maybe this is of some help: The shortest version is that you create a graph file in SNAP using the Graph Builder and save it as xml-file, some examples of such files are here:
For the way I do it, you have to modify these files saved from the Graph Builder:
- At the moment the nodes need to be in the order of processing in the xml file (even though they reference to each other).
- Remove any write node since the -t option in gpt is used
- in the read node define the input variable like here
https://github.com/npolar/RemoteSensing/blob/master/SNAP/Calib_Spk_TC25m_LinDB_EPSG3031.xml#L6-L8
Now you can call gpt from command line like, this, -Pfile means that “$file” in the xml file is replaced by the inputfilename:
gpt full_path_to_xml_file -Pfile="inputfile" -t "outputfile"
To process large quantities of data, I produce the command above as a string using Python and pass it to command line with os.system. You can also do this with Matlab and others…
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Hi Max, I have very similar problem.
Could have a look at my question please ?
I would really appreciate it.
Many Thanks,
Ishack
Hi Ishackm,
I would recommend providing gpt with a parameter file: https://senbox.atlassian.net/wiki/spaces/SNAP/pages/70503475/Bulk+Processing+with+GPT
Effectively, you will open your .xml graph file and replace file paths (or whatever other parameters you wan to provide) with ${variableName} and then within your parameter file, you will do
variableName=/this/is/my/path/to/my/s1product.dim
and then you can call gpt like so:
gpt my_processinggraph.xml -p myparameterfile.txt
Then you can just have a folder of these parameter files and do a loop like this (this is a bash shell loop, but you can do similar things on powershell or cmd on windows) :
for a in *.txt
do
gpt mygraph.xml -p $a
done
Hope that helps!
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NASA’s Introduction to gpt has some nice examples using an older version of gpt. Note that NASA has been renaming files, so it may be necessary to adjust some file names.
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