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Question

Making black No Data cells transparent in ECW raster mosaic


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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

zzupljanin
Contributor
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  • Contributor
  • March 29, 2017

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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  • Author
  • March 29, 2017

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


helmoet
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  • March 29, 2017

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.


Forum|alt.badge.img
  • Author
  • March 29, 2017
helmoet wrote:

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.

kampinga_c
Participant
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  • Participant
  • June 26, 2019
helmoet wrote:

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.


helmoet
Forum|alt.badge.img+8
  • June 28, 2019
helmoet wrote:

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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