But, In the above list (1+2, 2+2, 2+3, 2+4, 2+5…) which one i have to select as a master image?
there is no general rule for this. with 1+2 you capture the displacement based on a period of maybe 12 days, but with 2+5 this period is 36 days (if we assume 12 days between each subsequent pair).
Sometimes, longer periods result in more clear patterns, but they also suffer from higher decorrelation. On the other hand, it often depends on which incidents you want to analyze, e.g. if there was a specific date since something happened, so you place your image pairs around this incident.
If you want to understand the temporal dynamics of a longer time-span it is often good to add subsequent pairs (for high coherence), so 1+2, 2+3, 3+4 and then add up the displacements or visualize them over time in a graph. Check how this was done in this tutorial (slides are old but the last part on the multi-temporal analysis is still valid) https://eo-college.org/resource/insar_deformation/
Thank you ABraun.
stamps(2,2)
STAMPS: ########################################
STAMPS: ####### StaMPS/MTI Version 4.0b6 #######
STAMPS: ####### Beta version, Jun 2018 #######
STAMPS: ########################################
STAMPS: Will process patch subdirectories
psver currently: 1
psver now set to: 1
STAMPS: ########################################
STAMPS: ################ Step 2 ################
STAMPS: ########################################
STAMPS: Directory is PATCH_1
PS_EST_GAMMA_QUICK: Starting
PS_EST_GAMMA_QUICK: Estimating gamma for candidate pixels
GETPARM: filter_grid_size=50
GETPARM: filter_weighting=‘P-square’
GETPARM: clap_win=32
GETPARM: clap_low_pass_wavelength=800
GETPARM: clap_alpha=1
GETPARM: clap_beta=0.3
GETPARM: max_topo_err=20
GETPARM: lambda=0.0554658
GETPARM: gamma_change_convergence=0.005
GETPARM: gamma_max_iterations=3
GETPARM: small_baseline_flag=‘n’
Found look angle file
PS_EST_GAMMA_QUICK: n_trial_wraps=0.252487
PS_EST_GAMMA_QUICK: Initialising random distribution…
PS_EST_GAMMA_QUICK: 455435 PS candidates to process
PS_EST_GAMMA_QUICK: iteration #1
PS_EST_GAMMA_QUICK: Calculating patch phases…
Error using zeros
Requested 60459x155072x50 (1746.3GB) array exceeds maximum array size preference. Creation of arrays greater
than this limit may take a long time and cause MATLAB to become unresponsive. See array size limit or
preference panel for more information.
Error in ps_est_gamma_quick (line 215)
ph_grid=zeros(n_i,n_j,n_ifg,‘single’);
Error in stamps (line 326)
ps_est_gamma_quick(est_gamma_parm);
while running stamps(2,2), i’m getting this above error. please give me solution.
Thank you.
how many patches did you select during mt_prep_snap?
Seems like the raster is excessively large…
From Mdelgado comment,
I replace the ps_load_initial_gamma.m file in Stamps4.2b/matalb.
Then stamps(2,2) step is running nicely.
Thank you.
1 Like
interesting - thank you for reporting. I thought this was no longer necessary.
1 Like
stamps(6,6)
STAMPS: ########################################
STAMPS: ####### StaMPS/MTI Version 4.0b6 #######
STAMPS: ####### Beta version, Jun 2018 #######
STAMPS: ########################################
STAMPS: Will process current directory only
STAMPS: ########################################
STAMPS: ################ Step 6 ################
STAMPS: ########################################
STAMPS: Directory is 6_psiexport
PS_UNWRAP: Starting
Phase-unwrapping…
GETPARM: small_baseline_flag=‘n’
GETPARM: unwrap_patch_phase=‘n’
GETPARM: scla_deramp=‘n’
GETPARM: subtr_tropo=‘n’
GETPARM: tropo_method=‘a_l’
GETPARM: drop_ifg_index=
GETPARM: unwrap_hold_good_values=‘n’
PS_UNWRAP: Code to hold good values skipped
GETPARM: unwrap_time_win=730
GETPARM: unwrap_method=‘3D’
GETPARM: unwrap_grid_size=200
GETPARM: unwrap_gold_n_win=32
GETPARM: unwrap_prefilter_flag=‘y’
GETPARM: unwrap_gold_alpha=0.8
GETPARM: unwrap_la_error_flag=‘y’
GETPARM: unwrap_spatial_cost_func_flag=‘n’
GETPARM: max_topo_err=20
GETPARM: lambda=0.0554658
PS_UNWRAP: n_trial_wraps=0.261384
Resampling phase to grid…
Number of interferograms : 50
Number of points per ifg : 269037
Number of resampled points: 7915
Interpolating grid…
Number of unique edges in grid: 18636
Unwrapping in time-space…
Estimating look angle error (elapsed time=199s)
Using sequential daisy chain of interferograms
Smoothing in time (elapsed time=201s)
Unwrapping in space…
Processing IFG 1 of 50
Error using fread
Invalid file identifier. Use fopen to generate a valid file identifier.
Error in uw_stat_costs (line 159)
ifguw=fread(fid,[ncol,inf],‘float’);
Error in uw_3d (line 163)
uw_stat_costs(options.unwrap_method,options.variance);
Error in ps_unwrap (line 235)
[ph_uw_some,msd_some]=uw_3d(ph_w(:,unwrap_ifg_index),ps.xy,day,ifgday_ix(unwrap_ifg_index,:),ps.bperp(unwrap_ifg_index),options);
Error in stamps (line 503)
ps_unwrap
Please tell me the solution for this error.
Thank you
After replacing the ps_load_initial_gamma.m file in matlab folder. It is working up to stamps (5,5) without any interruption.
After finishing, the stamps(5,5). i run this below command as shown in stamps manual.
ps_plot(‘w’)
Warning: MATLAB has disabled some advanced graphics rendering features by switching to software OpenGL. For
more information, click here.
Color Range: -3.14159 to 3.14159 rad
ans =
Figure (1: w) with properties:
Number: 1
Name: 'w'
Color: [0.9400 0.9400 0.9400]
Position: [672 479 560 420]
Units: 'pixels'
Show all properties
While running stamps(6,6) i’m getting above posted error.
please check it once.
Thank you.
this looks like the case here where triangle was installed but the path was not correct in the config file. After you source the config file in the shell, you should be able to get the tool parameters when you type “triangle”. Please test.
Thank you so much ABraun… Its working
good job - great you found the error source!
Could you please shortly tell what you changed so people which also face this error can learn from it?
I didn’t installed Snaphu in my ubuntu platform, after installation of snaphu, directly using below command
sudo apt install snaphu .
stamps (6,6) running smoothly in matlab.
Thank you so much ABraun once again.
very good, thank you
Dear ABraun,
I processed upto stamps(8,8) steps successfully. Then how can i create time series for this data set.
Thank you.
Please tell me the time series generation steps after stamps(8,8)
Thank you
Please check chapter 5 of this excercise: http://eoscience.esa.int/landtraining2017/files/materials/D4P1a1I.pdf
Or you try the StaMPS-Visualizer, SNAP-StaMPS Workflow (instructions here)
Thank you so much ABraun.
Dear ABraun,
I try to run interferogram in SNAP for Stamps export,
But while generating the interferogram formation for all images (50 SAR images). The output is just generating one brust only instead of 5 brusts.
I reprocessed once again but still I’m getting same output (small area) instead of large area of coverage.
It is running from last 14 hours, still it is not completed.
Please give me suggestion,
Thank you.
I don’t really understand the problem, sorry. Maybe you can first describe how you prepared your data until the step of interferogram formation.
Did you see that there is a python script which does this job for you? Snap2stamps package: a free tool to automate the SNAP-StaMPS Workflow
Also well documented here: https://gitlab.com/Rexthor/gis-blog/-/blob/master/StaMPS/2-3_snap2stamps.md