Based on our discussion, I did mosaicking to make an ASTER DEM over my area of interest but as you know, ASTER is a very flawed DEM and has lots of values over water (figure1). I want to ignore values over water.
But, similar to ASTER, it was based on optical data. If you mask out the sea areas before the terrain correction, you can select “mask out areas without elevation” as I mentioned above.
I think “mask out areas without elevation” is under ‘terrain correction’ tool and I tried it but it says it is possible only for SAR images but I want to apply on ASTER DEM.
Yes, applying terrain correction on the ASTER DEM doesn’t work. You have use the product after “phase to elevation” and just repeat the Terrain Correction step.
But as long as all pixels are valid in the ASTER mosaic, nothing will happen.
I again have same problem and although I converted bands and save them, again ask me below question.
Do you wish to include reference dataset into in your subset definition?
Then I chose ‘no’, result is saved but I cannot open the data but when I detete ‘valid pixels expression’ , then results will be opened but result has some extra part???
If the estimated raw storage size of your subset is 0.0 MB, your bands to export are only virtual.
Right-click these rasters > convert band and save your product. Close the product and open it again. You can then export parts of the product (single rasters) without being dependent from a maths expression.
Somehow, the products you want to export are dependent from the collocation flags. If they are not included, the output fails.
Is it an option to directyl work with the img files in the data folder instead of exporting GeoTIFFs? Both work fine in most GIS software.
The product is saved in dim format and when I tried to open in QGIS, it was failed. I used ‘add vector layer’ and ‘add raster layer’ but they did not work.
@ABraun
I had two DEM images for two different days.
first DEM (3546*3803)
Second DEM (3498*3713)
Although now pixels are same (3546*3803) after collocation for both images but one of them looks bigger that another one by eye (figure 1 ) but when I made difference map from them, everything was fine in SNAP (figure2) but when i deleted ‘‘valid pixel expression’.’ OR open difference map (img) in QGIS (figure3), then the extra part is obvious there.
I have two products from ASTER 1 SEC. They are listed here:
ASTGTM2_N70W157.tif
ASTGTM2_N70W157.tif
I tried to make mosaic from them by using (Raster…Geometric operation…mosaicing) and the result is OK and it is saved in ‘band 1’ but it also produced one extra band named ‘band-1-count’.
I am not sure if this has been discussed already, but I try to find it, and found none
Aniway, is it possible to merge two scenes of bistatic TanDEM-X and keep the format as SAR product?
My study area is longer than the TDX scene, and thus I need multiple scenes
I don’t have problem generate DEM one by one
but it seems there are strange results because phase unwrapping is performed separately
the DEM from SNAP seems tilted perpendicular to the acqusition direction, so I need to remove the trend
I try SAR mosaic to merge them, but the output is not SAR product anymore, and thus I cannot make interferogram out of it