Incidence angle data with SNAP

[Kerstin Äkke]

I followed the preprocessing guide at https://github.com/insarlab/MintPy/wiki/SNAP-input-data.

When I run SmallbaselineApp all steps (correct_unwrap_error skipped) are successful until correct_troposphere step. There I get error:

Traceback (most recent call last):

  File "/export/sille/python/MintPy/mintpy/smallbaselineApp.py", line 1090, in <module>

    main()

  File "/export/sille/python/MintPy/mintpy/smallbaselineApp.py", line 1080, in main

    app.run(steps=inps.runSteps, plot=inps.plot)

  File "/export/sille/python/MintPy/mintpy/smallbaselineApp.py", line 1030, in run

    self.run_tropospheric_delay_correction(sname)

  File "/export/sille/python/MintPy/mintpy/smallbaselineApp.py", line 762, in run_tropospheric_delay_correction

    tropo_pyaps3.main(scp_args.split())

  File "/export/sille/python/MintPy/mintpy/tropo_pyaps3.py", line 575, in main

    get_delay_timeseries(inps, atr)

  File "/export/sille/python/MintPy/mintpy/tropo_pyaps3.py", line 505, in get_delay_timeseries

    inps.inc = geom_obj.read(datasetName='incidenceAngle')

  File "/export/sille/python/MintPy/mintpy/objects/stack.py", line 615, in read

    ds = f[familyName]

  File "h5py/_objects.pyx", line 54, in h5py._objects.with_phil.wrapper

  File "h5py/_objects.pyx", line 55, in h5py._objects.with_phil.wrapper

  File "/export/sille/.conda/envs/mintpy/lib/python3.7/site-packages/h5py/_hl/group.py", line 262, in __getitem__

    oid = h5o.open(self.id, self._e(name), lapl=self._lapl)

  File "h5py/_objects.pyx", line 54, in h5py._objects.with_phil.wrapper

  File "h5py/_objects.pyx", line 55, in h5py._objects.with_phil.wrapper

  File "h5py/h5o.pyx", line 190, in h5py.h5o.open

KeyError: "Unable to open object (object 'incidenceAngle' doesn't exist)"

Based on the guide and https://groups.google.com/d/msg/mintpy/fj8FFBRfuas/AW1Uzh5UAQAJ, providing the terrain corrected dem should be enough.

Can I somehow generate the incidence angle data from the dem file myself, since it doesn't appear to be created automatically?

[Yunjun Zhang]

Hi Kerstin,

Yes, you could generate it yourself using $MINTPY_HOME/mintpy/incidence_angle.py (check its help for detailed usage) and then specify the path to the template file to be loaded into “inputs/geometryGeo.h5” file.

Both incidence_angle.py script and the load_data.py are calling the function below internally, with input of some metadata (listed in the comments) and/or DEM. 

https://github.com/insarlab/MintPy/blob/master/mintpy/utils/utils0.py#L60

Since it’s not automatically created in your case, I am wondering if all the required metadata are there: you could run info.py to check it.

Yunjun

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[Jeanine Engelbrecht]

Dear Yunyun,

Thank you for this post. I had a similar problem to Kerstin and including the incidence angle file solved the issue. However, on running PyAPS with the new geometry file I am presented with a new error. I get to the point where the absolute delay for each day is calculated outputting the message:

 ------------------------------------------------------------------------------

calcualting absolute delay for each date using PyAPS (Jolivet et al., 2011; 2014) ...

number of grib files used: 24

Traceback (most recent call last):

  File "/home/jengelbrecht/python/MintPy/mintpy/smallbaselineApp.py", line 1134, in <module>

    main()

  File "/home/jengelbrecht/python/MintPy/mintpy/smallbaselineApp.py", line 1124, in main

    app.run(steps=inps.runSteps, plot=inps.plot)

  File "/home/jengelbrecht/python/MintPy/mintpy/smallbaselineApp.py", line 1074, in run

    self.run_tropospheric_delay_correction(sname)

  File "/home/jengelbrecht/python/MintPy/mintpy/smallbaselineApp.py", line 806, in run_tropospheric_delay_correction

    tropo_pyaps3.main(scp_args.split())

  File "/home/jengelbrecht/python/MintPy/mintpy/tropo_pyaps3.py", line 603, in main

    calculate_delay_timeseries(inps)

  File "/home/jengelbrecht/python/MintPy/mintpy/tropo_pyaps3.py", line 551, in calculate_delay_timeseries

    tropo_data[i] = get_delay(grib_file, inps)

ValueError: could not broadcast input array from shape (7094,8760) into shape (1661,2215)

Could you please provide any guidance on the cause of this error? I would value your guidance in this regard.

All the best,

Jeanine

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[Jeanine Engelbrecht]

The problem here was that the subset that was applied in the load_data phase was applied to the input interferogram datasets but it was not applied to the geometry datasets as well. I manually subsetted the Geometry datasets prior to loading and this solved the problem

[Yunjun Zhang]

Hi Jeanine,

I am glad to hear the problem is solved.

Yunjun