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Question

Finding No Data in ECW File

  • December 4, 2012
  • 3 replies
  • 15 views
adrian
Contributor
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Hi,

 

 

I have been provided an update of aerial photography in ECW format, I know that some of these files contain areas of black, i.e. there is no new photograph for this area.   I was wondering if there is a way FME can look at each file and tell me is there it contains and area of No Data without me looking at each file individually?

 

 

Thanks

 

 

Adrain

3 replies

sigtill
Supporter
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  • sigtillSupporter
  • Supporter
  • December 4, 2012
Is the complete file black or can it be on the surrounding area so that only a part of the image is almost black? You can average all the pixels and if it is above 240, for all pixels and channels you can flag it as empty
The real SigTill
adrian
Contributor
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  • adrianContributor
  • Author
  • Contributor
  • December 5, 2012
It could be any part of the image although it tends to be around the edges.
sigtill
Supporter
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  • sigtillSupporter
  • Supporter
  • December 6, 2012
Then you can read all the pixels on the "frame" of the image and decide, if you have more than x numbers of almost black pixels chained together - you select this as a NoData- ECW.
The real SigTill

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