Closed loreabad6 closed 2 years ago
Example of a coregistration test with the Reference DEM from official Norway repos resampled to 30 meters. Our resulting DEM was warped to EPSG:25835
to agree with the reference.
Things to note:
This was the code used (note-to-self: temporal directory names, might change locally):
dem_align.py home/data/ref_dem/NDH_Alta_2pkt_2018_DTM_resample30m.tif home/data/ani_test/20200605_202008
10_elevation_EPSG25835.tif -mode nuth -mask_list none -outdir home/data/ani_test/test4 -res max -max_offset 500
Unstable areas were removed before co-registration. New issue is a horizontal shift on the resulting "aligned" DEM. See the docs repo here for updates.
Switching to an approach with xdem
however, horizontal shifts still happen with Nuth-Kääb
After successful extraction of elevation values from the InSAR process, a vertical coregistration shoul be performed. To do so, we include the
demcoreg
module within our workflow. This are some steps and points to consider:demcoreg
module relies on a separate conda environment: find out how to call it properly within the workflowref_fn
andsrc_fn
should be correctly defined: reference DEM would be our external DEM data, while the source would be the recently generated S1-based DEM; document this properlydemcoreg
selects surfaces for coregistration that might not always be stable: make sure to document the need of a mask layer, in our case, that removes the landslide area and when relevant the water and coast areas. See figure in comments 🖼️