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.inc and .ls_map have different range

Added by Cynthia Chen almost 4 years ago

Dear GAMMA Users,
I used gc_map2, and generated .inc and .ls_map, I used the following commands to generate .inc and .ls_map in geotiff format.
data2geotiff EQA.dem_par EQA.20181112.ls_map 5 EQA.20181112. ls_map.geo.tif
data2geotiff EQA.dem_par EQA.20181112.inc 2 EQA.20181112.inc.geo.tif

I exported them to ArcGIS, finding that they have different range (please see attached figure). .inc is bigger than .ls_map. Is that reasonable? Why?

By the way, is there an example about using TerraSAR-X satellite data to generate a DEM?

inc&ls_map.png (299 KB) inc&ls_map.png

Replies (6)

.inc and .ls_map have different range - Added by Charles Werner almost 4 years ago

Hello,

The reason for this discrepancy in the regions is that the calculation of the
layover-shadow map is computationally expensive and it is restricted to the
width of the slant-range data as shown.

.inc and .ls_map have different range - Added by Charles Werner almost 4 years ago

Hello,

The reason for this discrepancy in the regions is that the calculation of the
layover-shadow map is computationally expensive and it is restricted to the
width of the slant-range data as shown.

RE: .inc and .ls_map have different range - Added by Cynthia Chen almost 4 years ago

Thank you, Charles.
Is there an example about using TerraSAR-X repeat-pass data to generate a DEM? Or should I refer to the 'README_TDX_demo_Etna' ? But this demo aims to TanDEM-X data. Is it proper to generate a DEM using TerraSAR-X repeat-pass data following this TanDEM-X demo?

RE: .inc and .ls_map have different range - Added by Charles Werner almost 4 years ago

Hello,
The method with Terra-SAR-X would be similar, There is no demo for Terra-SAR-X.

1. Create a differential interferogram of the scene with the existing DEM and
unwrap the phase.
2. use the program dh_map_orb to calculate the correction based on the unwrapped
differential phase
3. update the DEM in the regions where there is unwrapped phase.

This can be run through a second time, using the updated DEM.

Best regards,
Charles

RE: .inc and .ls_map have different range - Added by Cynthia Chen almost 4 years ago

Dear Charles,
Thank you very much.

RE: .inc and .ls_map have different range - Added by Cynthia Chen almost 4 years ago

Dear Charles,
I also want to use sentinel and alos data to generate DEMs separately. Can I also refer to this process of TanDEM-X data?

1. Create a differential interferogram of the scene with the existing DEM and
unwrap the phase.
2. use the program dh_map_orb to calculate the correction based on the unwrapped
differential phase
3. update the DEM in the regions where there is unwrapped phase.

Best regards,
Cynthia

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