Unwrapping step

Microwave Toolbox
#1

hello,

image
image1920×1080 617 KB

according to step 6, does it mean that the input is the phase.hdr created after making the export or is it the subset product used as input in the export step?

#2

What subset are you talking about?

The first tab selects the reference phase (before unwrapping, opened in SNAP)
The second tab selects the hdr file of the unwrapped phase (after execution of snaphu, not opened in SNAP)

Please also have a look at this topic: Problem in Snaphu Import section

And this tutorial: Sentinel-1 TOPS interferometry

#3

hello,
the subset corresponds to the last result obtained just before the export.
i tried again it worked.
i got this as a result.

subset_0_of_IW2_2019-04-29_split_VH_Orb_Stack_esd_ifg_deb_flt_out_Unw_Phase_ifg_29Apr2019_23May2019
subset_0_of_IW2_2019-04-29_split_VH_Orb_Stack_esd_ifg_deb_flt_out_Unw_Phase_ifg_29Apr2019_23May2019886×694 112 KB

#4

looks quite random to me. Did you check the coherence first? How does the wrapped interferogram look like?

#5

subset_0_of_IW2_2019-04-29_split_VH_Orb_Stack_esd_ifg_deb_flt_out_dsp-1_TC_new_band_3_VH
subset_0_of_IW2_2019-04-29_split_VH_Orb_Stack_esd_ifg_deb_flt_out_dsp-1_TC_new_band_3_VH894×694 355 KB

but it is after terrain correction. it worth mentioning that the interferogram is very noisy.

#6

I’m afraid you cannot expect InSAR results from this coherence.
What’s your temporal baseline?

#7

the time duration is between 29 april 2019 and 23 may 2019

#8

probably your area is covered by vegetation which causes temporal decorrelation?
Some notes on this: How can we calculate the volume of displaced material with displacement band(displacement_VV)?

#9

yes, the sechilienne landslide is a vegetated mountainous area.

#10

landslides are always critical because they are non-coherent proceses.
Have you considered the Offset Tracking module instead?

#11

no i did not. what is this module?

#12
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#13

i will read it. thank you!

#14

in the first tab, i selected hdr file of the phase not the reference phase opened in snap.

#15

image
it is working!

#16

very good!

#17

so, it is not a problem if we choose in the unwrapping step, as an input the hdr file of the phase instead of the product opened in snap (i.e. the file used for the export step). the hdr file i am talking about is the one found in the output product resulting from the export step.

#18

actually, the Phase in SNAP is the same as the img/hdr exported into the unwrapping folder. They have the same size, extent, and information. It only gets messed up if subsets are made after the export, because then the reference product is no longer matching the dimensions of the unwrapped phase.

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