Question

Making black No Data cells transparent in ECW raster mosaic

  • 29 March 2017
  • 6 replies
  • 48 views

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I am creating an ECW raster mosaic from around 500 JPGs using the RasterMosaicker transformer, in FME 2015.1. The attached snapshot shows a test piece of the resulting mosaic, but ideally I would like the areas with no data to be transparent, not black. Is this possible? I have read some threads on a similar theme but I find the answers where bands are discussed difficult to understand as I don't have enough knowledge in this area. Is there a simple solution? Probably not! Many thanks.


6 replies

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Have you tried RasterInterpretationCoercer. Convert from RGB to RGBA and select to 'create alphaband from no data'. If black pixels aren't defined as nodata use RasterBandNodataSetter before RICoercer.

Cheers,

Želimir

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OK many thanks, @zzupljanin - I'll try and experiment with this.

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rastertransparancy.fmw I experimented with this, see attachment. Might also be a good tip to add transparance before mosaicking to avoid black backgrounds, see

https://knowledge.safe.com/articles/18764/setting-alpha-vs-nodata-color-and-numeric-data.html

Hope this inspires you @masoj1.

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rastertransparancy.fmw I experimented with this, see attachment. Might also be a good tip to add transparance before mosaicking to avoid black backgrounds, see

https://knowledge.safe.com/articles/18764/setting-alpha-vs-nodata-color-and-numeric-data.html

Hope this inspires you @masoj1.

 

Wow thanks, @helmoet , I'll try this too as soon as I can.
Badge +2

rastertransparancy.fmw I experimented with this, see attachment. Might also be a good tip to add transparance before mosaicking to avoid black backgrounds, see

https://knowledge.safe.com/articles/18764/setting-alpha-vs-nodata-color-and-numeric-data.html

Hope this inspires you @masoj1.

@helmoet, is there a way, i can get the attachment 'rastertransparancy.fmw'? The attechment in your reply doesn't work anymore.

Badge +8

rastertransparancy.fmw I experimented with this, see attachment. Might also be a good tip to add transparance before mosaicking to avoid black backgrounds, see

https://knowledge.safe.com/articles/18764/setting-alpha-vs-nodata-color-and-numeric-data.html

Hope this inspires you @masoj1.

@kampinga_c here it is again, though it is a bit of an oldy...rastertransparancy.fmw

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