Dear ABraun,
While running the SNAP i used around 53 images and it’s created 52 interferograms. And the same output i used in SNAP-StamPS then it created 50 interferograms instead of 52. From where i will find these left images in StamPS.
Thank you.
I don’t know what went wrong, sorry.
Maybe your master date was also included in the slaves folder?
Hi.
I have seen several articles to discover horizontal deformation and they have seemed quite difficult to understand or replicate the process with QGIS.
Perhaps the work that has convinced me has been the following:
However, I am still not clear about the process. That is why I would like to know if there is a manual or workflow to continue learning about insar.
Thank you very much for all the contributions
another question. how can I get standard deviation among all the analyzed points?
ps_plot('vs')
Hi, nobody has an answer to this post, about if there is any manual or workflow of vertical and horizontal displacement? @ABraun @mdelgado
and another question @thho ;
I understand that when graphing, the displacements are cumulative movements, that is, from the first date to the second date, has moved
8,147864 mm / year and from the second date to the third date -2.5341
mm / year, etc. However, if I do the sum of all these displacements and make the average, I do NOT obtain the same average speed that is obtained from the exported Matlab file, it is very likely that I am confused, someone could explain to me what happens with the average displacement since it seems strange to me that there are variations between dates of 8.147864 mm / year, -8.443398 mm / year, etc.
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Hi there,
Hope everyone is well.
@thho @ABraun @mdelgado
I wanted to understand what exactly a time series displacement plot of a persistent scatterer from STAMPS processing truly represents.
Viewing the results of @suribabu is it wise to say that the los velocity on each specific date, is the respective value (from the .csv file) represented in the graph?
And if so, by adding all of them would you get the cumulative displacement of that specific ps, in mm, over that whole period?
Also @thho could you explain why you have added an option of subr. offset in the application? After applying it do you extract the real displacement, by providing the first date as 0 velocity and the rest is respective to it?
Sorry for the long question 
Aster
I think the opposite is the case: The time-series plot is the relative displacement at a point over time. It does not show the velocity over time, because that would mean that the velocity constantly decreases. In real, it shows that scatterers at this place are continuously moving away from the sensor at a (more or less) constant speed.
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@thho @mdelgado @ABraun thank you for the quick response.
That is true, if I understand correctly, it is the relative displacement based on a reference point representing close to 0 or 0 motion (seen as stable over time)?
So in stamps,if ‘ts’ displacement values of each date are provided by getting the corrected unwrapped values (step 5 to 7/8) by interferograms produces by the using same master, than each point represents the displacement of the master date and the slave date.
For example: say the first date 20171102 has a value of -17 mm and the master date is 20181207, than that value, shown in the 'ts’plot, is the displacement between those 2 dates.
Is that correct?
And if so, my main concern is if there a way to generate the cumulative displacement over time like other software ( such as sarproz etc.) produce?
I would be great to achieve such products so we could share and easily explain these products to non-eo specialist it’s already difficult to explain Los velocity results…
Hope you can help.
Aster
I think the time series plot shows exactly what you just described. Or am I missing a point?
can you please share an example?
Hi @ABraun,
sure The example is on page 7 of this article. It is referring to the option in SARPROZ to create a cumulative estimation.
https://www.ias.ac.in/article/fulltext/jess/129/0146
I would also like to understand why his ‘ts’ plots always start with 0 although the are ps estimation and his cumulative value falls perfectly with his last date value on the plot. If anyone knows how, please let me know.
Hope this helps.
Aster
the image you refer to shows the same information as the time series plot of StaMPS, the only difference is that the latter starts at y=0 (as you say).
I think this can be easily changed with matlab code, but I am not very experienced with it, so maybe someone else can answer this.
That is what the subtract offset button in the StaMPS-Visualizer does, though not in StamPS in Matlab and neither do I know from the top of my head how to accomplish that, but should not be to hard.
However, @asterios_papas, much of the plots is relative and I alwys need some time to wrap my head around it ;). If I do understand the PS plot of StamPS right, they are relative to the prime date, hence the first date does not start at 0. What the StamPS-Visualizer does is to simply offset all measurement points (MP) in order to let the curve start at 0 on the first date.
Lets discuss an example:
Assumptions:
- you have this series of images [t-1, t, t+1] where t is the prime date
- lets assume that we look at a MP on a slope that from t-1 constantly moves downslope.
- also MP’s position is along the line of sight (LOS) of our sensor
- lets assume we have just ascending images, and the slope we look at is west->east orientated (so S1 would look downslope and therewith in the direction the MP moves)
In this setting, we would have this time series plot:
- in t-1 the point is relative to t upslope therefore its displacement is positive
- in t the point is relative to t…well exactly the same hence 0
- in t+1 the point moved (in this example a bit slower, hence the slope is less steep) further downslope and lies in t+1 beneath t, hence -1 mm displaced relative to the t position.
If you want to get a “cumulative” displacement (the entire distance the MP has moved from t-1 to t+1) you have to subtract the offset:
In publications, I recognized, that cumulative displacement is used more often.
So, this is how I explain it to me, comments on that?
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Dear @thho
I have problem to install R, using the following commands:
./configure
make
‘make’ does not existe , what shall I do
Thanks
please provide proper system information:
Which OS and version
Which R version
From which source does the download come from
If you are on Ubuntu simply follow this
@thho I success to install R and rstudio from : https://linuxconfig.org/how-to-install-r-on-ubuntu-20-04
but the application doesn’t launch, have look please
Capture d’écran de 2020-12-15 10-58-05|690x388
failed to install leaflet package, so I downlod ‘‘leaflet_2.0.3’’ and I put it in the directory R/x86_64-pc-linux-gnu-library/3.4, after that I rerun the script but also it failled !!!
Here is the error:
install.packages(“leaflet”)
Installing package into ‘/home/smiloudi/R/x86_64-pc-linux-gnu-library/3.4’
(as ‘lib’ is unspecified)
Warning in install.packages :
dependency ‘raster’ is not available
essai de l’URL ‘https://cloud.r-project.org/src/contrib/leaflet_2.0.3.tar.gz’
Content type ‘application/x-gzip’ length 2039454 bytes (1.9 MB)
downloaded 1.9 MB
ERROR: dependency ‘raster’ is not available for package ‘leaflet’
- removing ‘/home/smiloudi/R/x86_64-pc-linux-gnu-library/3.4/leaflet’
Warning in install.packages :
installation of package ‘leaflet’ had non-zero exit status
The downloaded source packages are in
‘/tmp/RtmpDs3jta/downloaded_packages’
First guess is, that your Ubuntu installation is missing some dependencies, otherwise installing such standard R packages does not cause such errors. My advice is:
- avoid downloading and putting R packages by hand into folders, use this as a last option and before, try to figure out what causes the installation error.
- R 3.4 is rather old, try to install 3.6 at least (latest release is 4.0) I use 3.6 on Ubuntu 20 and this does the installation without troubles
- The error for leaflet installation is pointing to the missing raster package dependency. raster uses sp which relies on gdal, R uses the libgdal-dev library. To add it to you Ubuntu run this in Ubuntu terminal:
sudo apt install gdal-bin libgdal-dev -y
- after that return to R and run:
install.packages("rgdal")
install.packages("raster")
install.packages("leaflet")
@thho Thank you this makes absolute sense.
I’d like to point out that it is quite weird that this the first time anywhere that I’ve seen how time-series stamps analysis, or any other to be frank, are interpreted and explained decently. Not even in the manual…
So thank you @thho for being polite and honest enough to help out.
Aster
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