this is the third time i unwrapping my product in snaphu .
here are the all file information
i am really worried … i dont know how to solve it…
i am doing the same step that you mentioned … import the filter phase as input reference …
Your unwrapping folder starts with subset_of_subset_of_…
Your Reference product starts with S1A_
It is obvious that they are of different origin.
ohh i finally made it… thank u for your valuable comment
this is the google earth view of the unwrapped phase values … it ranges from -2.52 to 2.51 is the value in meter. or cm … how can you convert the values in meter … this the image of Nepal kathmandhu … is it ok
i want to create a subsidence zonation map only over Kathmandu because i could’t find any clear fringes… in coherence phase i found that over khatmandu the coherence values are high … so is it possible to wipe out the other pixel and take only the pixel which has higher coherence along with their corresponding phase value (by band math).
and any how these final coherence values are opened in arc gis software
Use “phase to displacement“ to convert the unwrapped interferogram to cm.
Use different image pairs if you need better fringes. Some documents with hints:
from where i get the wavelength information … and tell me the procedure to get the displacement in LOS and vertical displacement information …
in metadata two information are there incidence near and far which one i am gonna use …
with “phase to displacement” you don’t need any information.
If you want to calculate it manually, the wavelengths of all known satellites can easily found from their homepages or wikipedia.
Please use the search function, many of your questions were already answered several times:
with “phase to displacement” you don’t need any information.
If you want to calculate it manually, the wavelengths of all known satellites can easily found from their homepages or wikipedia.
Please also use the search function, many of your questions were already answered several times:
I use the following expression for LOS displacement.
another thing someone in this forum said about local incidence angle … how we can obtain local incidence angle
use the incident_angle band in the band maths instead a tie-point-grid so you have an exact value per pixel.
did you process all data as BEAM DIMAP format? These tie-point grids are part of every radar data which is loaded into SNAP.
Have a look if it is present before unwrapping.
yes, it presents in original sentinel image I found the incidence angle file in metadata tab … but when i unwrapped it and apply band math on it the incidence angle information is not available… i am asking you from where i get information when i applying the band math on unwrapped phase like in case of your image…
if you correcly import your unwrapped phase, the metadata (including the incident angle band) is copied into the imported product.
Have a look at this tutorial which shows all included steps (the unwrapping comes at 42:40)
i calculated the LOS displacement map… and this is my coherence image … here i excluded the areas which have low coherence value… now i want the take the LOS disformation information of these pixels only and other ones i want to eliminate… is it possible
in a completely unkown area … whrere you have’t any knowledge about the areas of zero subsidence … i can take the pixels whose coherence value near 1 as the areas where i supposed asume there is no change.
there can also be enormous change with full coherence at the same time. I would then rather go for the pattern of the displacement as well and select a point which is outside the area where the displacement rapidly changes.
InSAR measurements are relative - if there’s no “stable area” one can still detect relative differences between the movement of scatterers (one area moving faster than the other).
yes, but many S1 image pairs produce pseudo “displacements” which are just ramps caused by the (often really small) perpendicular baselines or improper orbit handling. In such cases, speaking of relative displacements would be a bit misleading.
I’d say it depends on the size of the patterns. If there are local fringes or peaks/holes, it is more likely to be a real displacement thant an overall trend superimposing the whole image.
Only massive earthquakes cause displacements at the scale of a Sentinel-1 footprint. One should not generally trust any calculation without thinking about plausibility.
