4.1 Radar Demo
Test area and dataset: optical image over the Jakobshavn glacier where the red rectangle marks boundary of the Sentinel-1A/B image pair (20170221-20170227). Input files in this test scenario consist of the Digital Elevation Model (DEM), local surface slope maps (in both x- and y-direction) and motion velocity maps (in both x- and y-direction) over the entire Greenland, where all maps share the same geographic Cartesian (northing/easting) coordinate grid with 240-m spacing and spatial reference system with EPSG code 3413 (a.k.a WGS 84 / NSIDC Sea Ice Polar Stereographic North).
Output of "Geogrid" module: (a) range pixel index at each grid point, (b) azimuth pixel index at each grid point, (c) range pixel displacement at each grid point, (d) azimuth pixel displacement at each grid point. Note: only the portion of the grid overlapping with the radar image pair has been extracted and shown.
This is obtained by implementing the following command line:
With ISCE:
testGeogrid_ISCE.py -m master_image_folder -s slave_image_folder -d demname -sx dhdxname -sy dhdyname -vx vxname -vy vyname -srx srxname -sry sryname -csminx csminxname -csminy csminyname -csmaxx csmaxxname -csmaxy csmaxyname -ssm ssmname
where "master_image_folder" and "slave_image_folder" are the folders storing master and slave image information (e.g. radar parameters), and "demname", "dhdxname", "dhdyname", "vxname", "vyname", "srxname", "sryname", "csminxname", "csminyname", "csmaxxname", "csmaxyname" and "ssmname" are defined below in the instructions.
Using the matrix of conversion coefficients, when fine pixel displacement are estimated from radar data, they can be immediately converted to motion velocity. See the final result below by using the matrix of conversion coefficients from the "Geogrid" module and the radar-estimated fine pixel displacement from the "autoRIFT" module (https://github.com/leiyangleon/autoRIFT).
Final motion velocity results by combining outputs from "Geogrid" and "autoRIFT" modules: (a) estimated motion velocity from Sentinel-1 data (x-direction; in m/yr), (b) motion velocity from input data (x-direction; in m/yr), (c) estimated motion velocity from Sentinel-1 data (y-direction; in m/yr), (d) motion velocity from input data (y-direction; in m/yr). Notes: all maps are established exactly over the same geographic Cartesian (northing/easting) coordinate grid from input.