# Question regarding Phase to Displacement and Time series tool in SNAP

Hi there

I have managed to unwrapped the phase and I used the phase to displacement tool to generate the displacements. Are these displacements LOS or vertical?

Also, how can I use the time series tool in SNAP (under RADAR)? I would like to see the displacement time series of a pixel between different pairs of INSAR images. The HELP tool does not seem to work.

Thanks!

Regards
Ben

Hi Ben,
I am also doing the same thing that you have asked above, were you able to find an answer to your questions?

Thanks,
Waqas

I think the answer of your question will be solved via release the SNAP 5, and answering the question of Ben, Yes, it is the Displacement LOS, or Line Of Sight.

@falahfakhri, when I convert the unwrapped phased to vertical displacement using the methodology of Subsidence map in 3d view then it is still in the range of 4+ meters which looks a bit unrealistic.
I am analyzing the Nov 14, 2016 New Zealand earth quack site.

What is the reason of converting the Disp. from LOS to Ver.? I donâ€™t find any reason â€śPersonal Opinionâ€ť Also I processed this images you could find the results here

To correct my question!
When I convert the unwrapped phase to metric unit (meters), but even if it is in LOS phase or in metersâ€¦ their range is (-973.1 to 133.2 phase) and (-0.97 to 9.35 m) respectively.
What could I have done wrong?

these values of displacement are relative at first. You would then need to level it to zero elevation at some point.

However, the range of coarsely 10 m is quite hugeâ€¦

Thanks ABraun, This was based on the default coherence band of the interferogram and I guess that could be a reason that is why I am also now re-analysing the same with the masked coherence > 0.5, will share the next result as well.

I know that you have mentioned it in other posts as well to subtract the reference hight from the Unwrapped phase but was a bit unclear, can i figure out the reference height by masking the Unwrapped phase with the highest coherence??

the reference height would be at a point where you have high coherence and expect no change in the image. The displacement value at this point is the one to to level to zero (by adding or subtracting the respective value). If you then mask out all areas with low coherence the total displacements along the LOS should remain .

2 Likes

got it! many thanks

I would be interested if the range is still so wide after these steps. Maybe you can share your results with us