holes in point grid at fine spatial resolution

[hardreddata]

Hi,

I am enjoying exploring MintPy. Thanks again for sharing it.

It sounds like an exciting time for SAR with ICEYE and Capella Space entering the space.

Suppose I am trying to get the most resolution I can out of Sentinel.

The ISCE stackSentinel.py arguments after the data, orbit, aux, DEM and bounding box.

-r 3 -z 1 -f 0.5 -C geometry -u icu --start_date 2021-01-01

And then doing something very minimal with MintPy, after loading up the ISCE stack per documentation.

mintpy.networkInversion.weightFunc      = no #[var / fim / coh / no], auto for var 
mintpy.topographicResidual              = no  #[yes / no], auto for yes

Creating a shapefile save_qgis.py geo/geo_timeseries_ERA5.h5 -g geo/geo_geometryRadar.h5 I note the points are often chunked into in strips

Here this is a toy example with only three snapshots. I see the same thing when looking at years of data with more thoughtful parameters (NESD, Snaphu, MintPy network modification etc).

I wonder if this is because the SRTM DEM is only 30m? Or perhaps ISCE or MintPy isn't intended for such a small number of range and azimuth looks? I want to explore replacing ISCE with Fringe but have had issues isce-framework/fringe#41.

Advice invited.

[piyushrpt]

If you have a stack in radar geometry, you are much better of generating the point cloud from that rather than from geocoded results. Geocoding inherently will force it on to a 30m grid. If you are looking for resolution, the radar geometry lat/lon should be better. Coarser azimuth resolution will dominate and you will still see linear patterns with S1 data.

[yunjunz]

By default, mintpy is geocoding in roughly the same grid size as the input file in radar coordinates (resample.py#L327) using the nearest-neighbor interpolation. I second @piyushrpt recommendation on feeding the radar-coord files to save_qgis.py directly, especially for the high-resolution point cloud as your case.

[hardreddata]

Thanks!

I didn't strictly realise I could combine inputs and outputs in the save_qgis.py command. So many MintPy tricks to learn.

It looks much nicer now.