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Surface displacement using D-InSAR

Added by Kaian Shahateet about 5 years ago

Hello everyone,

I am intending to use Differential InSAR to evaluate surface displacement on James Ross Island in the northeastern of Antarctica.

Since I only want to generate surface displacement (2D) I made the assumption that the glacier flow occurs parallel to the slope. With that, I need 2 linear independent displacements, for example ascending and descending satellite trajectories.

Said that, I have used the reference manual of Gamma, Differential Interferometry and Geocoding Software -DIFF&GEO (Differential Interferometry – version 1.4 from June 2013), to generate the first. More specifically, the example B (2-pass differential interferometric processing without phase unwrapping).

On the step B6 (Generating displacement map), it is used the command dispmap, and it will generate a vertical displacement, and it is not my case.

Somebody has a methodology to proceed to generate a horizontal displacement using D-InSAR?

Thank you,

Kaian Fernandes


Replies (11)

Surface displacement using D-InSAR - Added by Charles Werner about 5 years ago

Hello,

You need to terrain geocode the LOS displacement for each pass to the same DEM
segment. For each DEM segment you need to calculate the look vector using
lk_vec_lt. then you can use the program dispmap_ENU
to calculate the displacement in East North and up coordinates.

It is possible to add constraints to the solution for the deformation, such as
that there is 0. motion in the direction perpendicular to the local surface.
this would mean that the ice flows along the local gradient. For that you would
have to calculate the surface perpendicular vector for every point in the DEM
(also in ENU coordinates) and then set the value to 0.

dispmap_ENU performs an SVD least-squares solution for the surface displacement.
See the documentation.

There is a Gamma demo for using dispmap_ENU:

https://1drv.ms/u/s!Ag_xahLucCVfiWtiIyzu6Q43AItT?e=XbO49J

Best regards,

Charles

RE: Surface displacement using D-InSAR - Added by Kaian Shahateet about 5 years ago

Hello Charles,

Thank you very much for your responsea, and this great tutorial!

I am trying to perform this tutorial, and some questions have arose.

- In part 1, step 4 = When I tried to perform condition_offset_estimates script, the LAT program single_class_mappinga is not available. Does it have a repository that I can install?

- In part 1, step 1 = it says:

"# based on the quicklook image from the zip file (*.png) we decide to use the
  1. last 2 bursts of IW1 of this data set plus 4 bursts from the following data set
  2. We edit the burst number table A174.burst_number_table to represent this
  3. decision"

How this decision came?

and also, how the A174.burst_number_table file became:

zipfile:              S1A_IW_SLC__1SDV_20171106T145146_20171106T145213_019146_02065F_6276.zip
iw1_number_of_bursts: 6
iw1_first_burst:      202.314987
iw1_last_burst:       207.314987

Sorry about so many questions,

Regards,

Kaian Fernandes

RE: Surface displacement using D-InSAR - Added by Charles Werner about 5 years ago

the program name is single_class_mapping not single_class_mappinga.
It is part of the LAT package. Do you have this package?

Please check again.

Best regards,
Charles

RE: Surface displacement using D-InSAR - Added by Kaian Shahateet about 5 years ago

Hello Charles,

The letter "a" at the end of "single_class_mapping" came due to a problem on my keyboard, I am sorry.

The package LAT is not installed on my computer. Could I download it?

Regards,

Kaian

RE: Surface displacement using D-InSAR - Added by Charles Werner about 5 years ago

Hello,
Check your license agreement, if you have the LAT or not as a package.
What OS and version are you running?

Best regards,
Charles Werner

RE: Surface displacement using D-InSAR - Added by Kaian Shahateet about 5 years ago

The software delivered is the binary code for LINUX of the modules:
ISP
DIFF&GEO
DISP

My OS is Ubuntu 18.04.2

Regards,

Kaian

RE: Surface displacement using D-InSAR - Added by Charles Werner about 5 years ago

Hello,
What is the name of the script you are calling that requires single_class_mapping?

RE: Surface displacement using D-InSAR - Added by Kaian Shahateet about 5 years ago

It is the "condition_offset_estimates" on the part 1, step 4 of the tutorial.

RE: Surface displacement using D-InSAR - Added by Kaian Shahateet about 5 years ago

Hello Charles,

Would you have any advice about this issue?

Cheers,

Kaian

RE: Surface displacement using D-InSAR - Added by Charles Werner about 5 years ago

Hello,

I strongly recommend getting the LAT package with the software. There are many
very useful temporal and spatial filtering, classification, and polarimetric
programs in the package. Please ask for a quote. I think it is very well worth
the expense.

Best regards,
Charles Werner

RE: Surface displacement using D-InSAR - Added by TARIQ ASHRAF over 1 year ago

I know I am quite late to show up but can i get this demo also ? Since i cant find it with the link mentioned above. Gamma demo for using dispmap_ENU:

https://1drv.ms/u/s!Ag_xahLucCVfiWtiIyzu6Q43AItT?e=XbO49J

    (1-11/11)