I got through Sentinel-1 TOPS and subsequent operations on the way to interferometric displacement, but choked at the Band Maths Expression in the Re-calculate Interferometric Phase step.
Thanks for reply, I tried dates in various formats, the string I used is from the pdf cookbook, so the question is how to configure the expression for my data?
I ran various versions of the expression, changing the date format, the error message was something about the 01Jul2017_07Jul2017 string not recognized.
Is the date string critical to the process or just a name?
If the Expression Editor brings the correct string from the input file, I think the problem is solved and thank you very much! I just have to build the correct expression and have a template for what it should look like.
If the string comes from the original S1 data package, I missed it, I had dumped the original data to conserve memory. If the string is not in the process input file, I can get it from the original data package. That helps a lot, thank you v much. I have some work to do. InSAR in the hands of an old geologist is v, v cool!
Solved, the Re-calculate Interferometric Phase process works by constructing the mathematical expression as follows:
In the expression editor, I type atan2(
then click the [q_ifg_VV_ …] expression in the Data Sources list
then type the comma [ , ]
then click the [i_ifg_VV_ …] expression in the Data Sources list
then typed the close parenthesis [ ) ]
the expression atan2(q_ifg_VV_ …,i_ifg_VV_ …) is good, click OK.
However, we need to confirm the order of the data sources, the resulting images are different (inverse color pallet), depending on the order in the expression. q… first, then i… Correct?
Someone correct me if I’m wrong but using band maths, the results will always be in gray scale. You can manually change that in the color manipulation window.
For the “best” quide to S1, I think that there are already plenty of S1 tutorials here. I can also recommend the official ESA tutorials : http://step.esa.int/main/doc/tutorials/
Thanks, Quentin, it was band math in the Re-calculate Interferometric Phase that made the gray scale image.
Maybe the best InSAR displacement guide is
? A RUS webinar, 2017. In that guide, there is no Re-calculate Interferometric Phase step. At the tutorial link you suggested, it seems the S1 tutorial are a few years old, difficult to follow in latest S1TBX?
I’ve been through the process, including Snaphu, did not get the expected displacement result for the recent Anak Krakatau landslide, but learned a lot. Many thanks for your help, Ken