thank you ,in band maths I import like this
if you enter a condition in the band maths, all pixels which fulfill this logic are 1 (white), all others are 0 (black)
You have to enter it in the valid pixel expression of the Backscatter band to really exclude them.
But if the shadow pixels are so few, why do you care about them at all?
my teacher says my reseach area have many mountains ，and the altitude is about 2000-3000meters,so my reseach area will be affect deeply by shadow and terrain.so these days I just want to find a way to solve the problem
I think you are already tackling this issue by simply calibration to Gamma0 with the terrain flattening.
You can then still mask out the pixels which are real shadows (no signal from the ground).
you means use Gamma0? I always use sigma0,so i will change right now.and i try
IF layover_shadow_mask >= 2 THEN NaN ELSE Sigma0_VV in the band maths,the result is like this
based on your screenshots above, only few pixels are 2 and above. If you use another shadow mask, please adjust it to the value which indicates faulty data.
The example I showed above only works if the correct pixels are 0 in the mask
as you say,I do the calibrate with Gamma0 ,then the terrain flattening,after this i do the SAR Simulation Terrain Correction which has an extra option ro output shadow and overlay areas. the result is like this,so how can i exrtact the shadow which value coding is 2 and 3?do use band maths and import:layover_shadow_mask>=2? and my reseach is about soil moisture,so i need use sigma0,but here i use gamma0,how can i do with this?
open the band properties of Gamma0_VV and Gamma0_VH and enter
layover_shadow_mask == 0
in the valid pixel expression
this removes all areas which are geometrical shadows from your (already radiometrically corrected) image. I think you cannot do much more.
ho,I have found the shadow file in mask,yes,this profile match the image shadow，and i want to ask how can i use this file to clip my sigmo0 image
determine the value which indicates shadow in the band Shadow
and enter the valid pixel expression accordingly, just as in my example above.
you inserted it in the wrong line, you need to define which pixels you want to use (all which are 0 in the mask) in the valid pixel expression
layover_shadow_mask == 0
ok ,it’s great.thank you very much .i have solve my problem.It’s very kind of you for so patient to answer my question.Best wishes to you.
we are here to help
hello ABraun,I have another question what does the rough statistics mean? i want to use the sigma0 to reseach the soil water,should I click the rough statistics button,will the sigma0’s value change?
this just means that the histogram shown in the color manipulation (and the min/max) values are not based on all pixels but only a small proportion. If you wanted to get to know the absolute maximum (or mean or whatever) you need to use the statistics tool (the E icon). But for the distribution of colors over the color range, it is sufficient.
The pixel data is not affected by the Color manipulation tab at all, just the assignment of grey values.
thank you very much.you really help me a lot.:玫瑰:
give it a try
ok,thank you very much!