Hi Katherine, can you please tell what is the solution to this problem ? My pscands.1.ij file is empty too …
if this file is empty it is probably related to a bad interferogram. when running mt_prep_snap check the mean amplitude(should not be zero) and amount of cells with 0 amplitude(should not be higher than cells with amplitude). you can also visually check the interferograms in SNAP. @houda
so if i have a bad interferogram i have to delete from diff0 and rsc the files that have the date of the bad inteferogram ? Is this solution enough to correct the problem? @Gijs thank you for your time
@houda yes if you remove all files containing the date of this ifg in the stamps_export folder this date will not be processed in mt_prep_snap and i should solve the error.
you could also try to reprocess that date and maybe that will fix the file, common problems are:
- accidentally putting a descending file in your ascending file (or vice versa)
- accidentally split the wrong subswath
- accidentally put file of different path/frame in the project folder
i have also had cases where the Sentinel 1 file was just corrupt 
but just removing the date will solve your problem.
Hey everybody,
a small question:
When plotting a time series plot on ps_plot(‘v-do’,‘ts’) for some reason the interferograms i have listed in drop_ifg_index and scla_drop_index are still shown.
i redid the processing with drop_ifg_index from step 1 again so i am not sure how this data is still showing.
do you guys have any clue?
Did you followed this,
If there are unwrapping errors in some images, you can drop them from the spatially-
correlated error estimation. E.g. to drop the 2nd and 24th interferograms
setparm(‘scla_drop_index’,[2,24])
Then rerun Step 7.
Source
StaMPS Persistent Scatterer Exercise
ESA Land Training Course, Bucharest, 14-18th September, 2015
this is not my question, and yes ofcourse i have done this.
drop_index looks like this [1,2,3,4,6,7]
but for some reason ifg 3,4,6,7 still show as ts points in the v-do ts plots
I got your question mean very well, but I’m asking if you drop those unwanted correctly,
Use the command such as
setparm(‘scla_deramp’,‘y’) If you want to apply it, or
setparm(‘scla_deramp’,‘n’) if you do not want to apply it
yes of course i did 
if i type getparm it shows the correct value and this also gets reflected when running the stamps steps.
Is there anybody who can enlighten me? (@thho @ABraun @mdelgado )
i am quite stuck since these ifgs really do not fit the data and implement too much noise.
as @falahfakhri already discussed with me, i have indeed set the parameter correctly and it does reflect when the stamps steps run but somehow the dates still show in the timeseries plots.
I am not sure you are using properly the command to plot the ts not considering the dropped ifgs. Please check the full usage of the ps_plot function.
Still, I am not fun of dropping data for ‘introducing noise’ as it is not really noise, but signal with unknown behavior, and this is what science does… get the answer to the unknowns. Still… try to plot it using full command (or try to restart StaMPS from mt_prep_snap step by removing the data you do not want to)
you mean that even though i have dropped the ifgs i still have to plot like this:
psplot(‘v-d’,1,0,0,[1:3,7:8],‘ts’) ?
And @mdelgado , I am working on a permafrost area so the dates i want to throw out are when ice was still on the ground or dates during heavy snowfall. But thank you for the tips anyway.
I guess so, try to use the full command and let us know.
Cheers
Dear Andy, I’d like to raise this issue once more, concerning python, Would you please to take a look at the following discussions and give me your opinion,
Hey everybody,
i have been trying to see the impact of stamps step 8 on the deformation for a long time now and finnaly figured out it only works when plotting u like this. ps_plot(‘u-dmos’,1) is there any way to subtrac s vrom the velocity plot aswell. i use v-dao, a_linear now but would like to see the difference between stamps and train since the train correction doesnt really impact the data.
Greetings,
Gijs
edit: nevermind, i reread the manual twice and found out the mand o options are mutually exclusive with the s option since they both represent the same error. so v-ds works.
1 Like
Hey everybody,
coming back on above question i am now trying to compute the standard deviation for the velocity using ps_plot(‘vs-ds’) bur this creates this error:
unknown subtract flags
Error in ps_plot (line 1835)
fig_name_tca=ps_mean_v(ifg_list,1500,value_type(4:end),use_small_baselines,aps_flag);
which i think, has to do with the fact there are 2 s’s in the ‘’.
anyone know how to compute the vs when subtracting the s of step 8.
That means that the type vs-ds is not defined in the ps_plot.m function.
I suggest you to open the file and define it manually, based on previous types which should contain vs and -ds .
does filter should be done in the Interferometric image befor remove the topoPhase,the manual does not shows the filter
Filtering should work better after topo-removal as the interferogram will have fewer fringes.
If you want to perform PSI you should not do any phase filtering, otherwise point scatterers are not any more point, but their influence is distributed.