SNAP processing

This module contains Python wrappers for SNAP to extract Sentinel-1 bursts containing your Area of Interest (AOI) and co-register them into a stack of images within a common reference geometry. Sentinel-1 data of your AOI should be already downloaded and accessible locally or via the network filesystem. For automatic download, see Sentinel-1 data download.

Burst extraction

For each stack covering your AOI, prepare input parameters file snap.parms:

{
"SNAP_parameters" : {
    "snapPath" : "/home/rc/sw/snap/bin/",          # path to SNAP binaries
    "repoPath" : "/home/rc/sw/gecoris/gecoris/",   # path to gecoris
    "ram" : 100000,                                # [MB]
    "cores" : 64                                   #
},
"Stack_parameters" : {
    "workDir" : '/home/rc/CR_Partizanske/DSC124/', # processing directory
    "dataDirs" : ('/home/rc/SNT1/DSC124/',),       # tuple of paths to SLC data
    "swaths" : ('IW1',),                           # tuple of all usable swaths
    "min_lon" : '18.34054',                        # Specify  AOI corners:
    "max_lon" : '18.34055',
    "min_lat" : '48.63017',
    "max_lat" : '48.63018',
    "startDate" : '20190730',
    "endDate" : '',                                # leave blank to use all SLC
    "masterDate" : ''                              # leave blank to select optimal
}}

This wrapper calls SNAP to extract corresponding bursts and download precise orbits:

python gecoris/batchPrepare.py snap.parms

Extracted SLC bursts are stored in slaves directory under your workDir specified in input parameters.

Note

If your AOI spans multiple subswaths, you must specify all of them in swaths parameter as a comma-separated tuple.

Co-registration

For InSAR processing and SCR predicition co-registered image stacks are required.

First, you must choose the master (geometric reference) image either automatically, minimizing temporal and geometric baselines:

python gecoris/getMaster.py snap.parms

Or it can be selected manually and placed in the master directory under your workDir.

Co-registration is then performed by:

python gecoris/batchCoreg.py snap.parms

Note

Current implementation uses single-master configuration, geometry-based co-registration and ESD correction. Sub-swath wise.