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Error clipping raster data with polygon shapefile

  • 29 August 2017
  • 9 replies
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Hello,

I have a lot of rasters to clip with a single polygon shapefile. As always, I use the 'clipper' function in FME in a simple workspace. But I am unable to clip the data, FME gives me the following error message:

MaskCombiner(RasterEvaluationFactory): Failed to parse the EXPRESSION_LIST clause. The provided value was 'if(B[0]==255,A[0],nan);if(B[0]==255,A[1],nan);if(B[0]==255,A[2],nan);if(B[0]==255,A[3],nan)'. Please ensure that your syntax is correct

I am guessing that something is wrong with the nodata value in my tiff files? How do I fix this issue in FME?

Thanks!

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Best answer by courtney_m 29 August 2017, 16:43

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9 replies

zzupljanin
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Interesting, did you try to use RasterBandNoDataSetter before clipping

takashi
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Are there some transformers that manipulate raster features, other than the Clipper? If you posted the workspace or its screenshot, it could help us to find the issue.

 

 

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Are there some transformers that manipulate raster features, other than the Clipper? If you posted the workspace or its screenshot, it could help us to find the issue.

 

 

@takashi: No, the workspace is as easy as it gets: read in the multiband geotiff, clip using an ESRI shapefile (with one polygon), and write as a multiband geotiff in a different folder. There are no other operations. Both datasets have the same projection, too, and can be opened in QGIS with no problems.

 

 

zzupljanin
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@takashi: No, the workspace is as easy as it gets: read in the multiband geotiff, clip using an ESRI shapefile (with one polygon), and write as a multiband geotiff in a different folder. There are no other operations. Both datasets have the same projection, too, and can be opened in QGIS with no problems.

 

 

can you maybe provide data sample?
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As @zzupljanin, mentioned, you can try adding a transformer before clipping. Another option would be the RasterBandNoDataRemover or the RasterInterpretationCoercer. If you can attach your workspace and sample data, I can try this out.

mark2atsafe
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Looks like this is a known issue (PR#77325). Where the nodata is set to NaN (Not a Number) then there is a problem. As others have suggested, using a RasterBandNoDataSetter to change the Nodata value to an actual number is a good workaround.

If you need to follow up on this, contact our support team and let them know it is related to PR#77325

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As @zzupljanin, mentioned, you can try adding a transformer before clipping. Another option would be the RasterBandNoDataRemover or the RasterInterpretationCoercer. If you can attach your workspace and sample data, I can try this out.

Using RasterBandNoDataRemover solved my problem, thanks @courtney_m!

 

mark2atsafe
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Userlevel 4
Badge +25

Looks like this is a known issue (PR#77325). Where the nodata is set to NaN (Not a Number) then there is a problem. As others have suggested, using a RasterBandNoDataSetter to change the Nodata value to an actual number is a good workaround.

If you need to follow up on this, contact our support team and let them know it is related to PR#77325

fyi It's been fixed in FME2018 (beta build 18170 or greater)

 

daveatsafe
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The issue with the Clipper that was causing this problem has been fixed in FME 2018, which can be downloaded from www.safe.com/download.

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