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Question

overlaying 2 rasters using rasterMosaicker , only one image appear

  • December 13, 2022
  • 2 replies
  • 88 views
E

Hello:)

i'm trying to overly 2 rasters :

1- orginal raster (orthophoto)

2- bounding box of the original raster as a boundig box rectangle +100 offset

i'm using rasterMosaicker , but the result only shows the rectangle and not the orthophoto

i tried sorting - didn't help  

see the attached workflow and parameters:

imagethe result that i'm getting in the inspector which is the correct one - black rectangle + orthophoto:

imageresult that i;m getting after the mosaicker (only the black rectangle):

imagewhy i'm getting different result from the inspector ? the parameters for the mosaicker are:

imagethanks

2 replies

birgit
Influencer
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  • birgitInfluencer
  • Influencer
  • 131 replies
  • December 14, 2022

Sounds kind of buggy. I haven't used this transformer for overlapping rasters so I can't tell you the correct settings needed. I can suggest looking at the RasterExpressenEvaluator in the Two rasters mode. I once used these settings:

RasterExpressionEvaluator settings for replacing nodata cellsThe interpretation value depends on the data types in your raster and the expression used here basically replaces all cells with nodata values in raster A with the cells in raster B. You case raster B would be your black rectangle.

 

Also you can see in my example that I have group processing selected, you don't need that for your usecase.

🫠
virtualcitymatt
Celebrity
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  • virtualcitymattCelebrity
  • Celebrity
  • 2000 replies
  • December 14, 2022

You need to make sure that the data you want on top is coming in Last. The sorter should help, however, you need to make sure that you are sorting it correctly.

 

The alternative option which should also work is to change the "Overlapping Value" from "Last" to "Maximum". Black is RGB(0,0,0) - this will always lower than any color so the black pixel will never be chosen.


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