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Hi,

For a client we are developing a system to preview survey data (bathymetry) in a browser. Additionally, we also need to indicate differences between surveys over time. These survey data are supplied as rasters.

 

I have some troubles when reprojecting rasters with different extents to Web Mercator, please find attached a document with more information and screenschots.

 

Raster 1

  • CRS       EPSG:32643 - WGS 84 / UTM zone 43N - Projected
  • Extent  272800,2092300 : 276600,2097600
  • Unit      meters
  • Width   3800
  • Height  5300
  • Origin   272800,2097600
  • Pixel Size 1, -1

 

Raster 2

  • CRS       EPSG:32643 - WGS 84 / UTM zone 43N - Projected
  • Extent  261500,2088600 : 281600,2100300
  • Unit      meters
  • Width   20100
  • Height  11700
  • Origin   261500,2100300
  • Pixel Size 1, -1

 

 

I'm looking for a way to prevent small displacements using a correct combination of FME transformers, using FME 2020.1

 

Thanks,

 

Richard.

 

Thanks for the question @r_huesken​! Just wanting to get clarification on the issue you are having. If you are comparing 2 rasters with different extents, I would assume there would be areas that aren't overlapped. Are you hoping to clip any of the areas that are only covered by one survey?

Hi, there areas that do not overlap, but that's not my concern, since I'm looking at areas where the surveys overlap. I find that the top left coordinate and the raster width and height are important for transformation fromEPSG:32643 to Web Mercator (EPSG:3857). These are different for both rasters, are transformed rasters give different outlines and z values in areas where they overlap...

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