DEM generation with ALOS-2

Can you please give an example?

Sometimes, the topographic phase is modeled, removed before unwrapping of what remains and later added again. This is said to improve the unwrapping.

Topographic phase is removed for differential interferometry, for example for the detection of subsidence between two images. For DEM generation, you are highly dependent from the variation of the phase which originates from topography. How else would you describe it then without it?

ok,when i reference to envi sarscape insar DEM workflow,reflatting is processed,this is used to remove flatting ,does this step equals to topographic phase removal?

Sorry for come into your discussion, but @zhuhaxixiong this is the simple equations to get displacement or to get the topography

your picture really clarify the problem,but i want to know how does snap remove flat_earth phase(in sarscape a step called flatteing is dealed)?

another question in DEM generation I need to keep the topo phase,but how to remove flat_earth phase and disp phase in snap

Did you take a look at this tutorial,

It explains step and answers your question,

Also the following one,

really thank you,the flatt phase is removed during interferometry

when i choose phase to elevation,the result is black?

how to export dem to envi or arcgis format?

Please update snap and use the SRTM 1Sec in the Phase To Elevation module.
No export needed, the img files in the data folder are already GIS compatible and basically ENVI raster files. But your last step has to be Range Doppler Terrain Correction to put the data into a coordinate reference system.

this is my Phase_filter img in snap:

and compared to the sarscape :

there are so many fringe in snap picture

you means when transfor phase to elevation,which i shoud choose to generation DEM

It’s worth trying the other SRTM, yes.
About the fringes: much depends on proper coregistration and use of metadata. Did you apply orbit files as a first step?
The SARscape image looks like it’s already unwrapped (no more fringes)

NO,becasue my data was alos-2 not sentinel

Right, sorry.
SNAP still seems to have problems with ALOS orbits…

maybe i forget to check the sub flat-earth option

when i subset a area the interferometry looks right(no more fringes):

do you know how to differ the phase to heigh and phase to elevation?

You find many answers with the search function: Phase to elevation vs phase to height

Hello, I want to ask if there are two bands in generation DEM exported by SNAP. Band_1 and band_2 have different DEM data.