Skip to main content
Question

Mosaicing ECW without degradation

  • June 5, 2013
  • 5 replies
  • 30 views
C
Hello.

 

 

I'm trying to mosaic a large dataset (50GB/25000 files) of ECW-files into 17 mosaics.

 

One of the problems I encounter is the fact that the mosics are degraded compared to the orginal ECW files, which is of course unfortunate.

 

 

Any ideas on how I may resolve this problem?
This post is closed to further activity.
It may be an old question, an answered question, an implemented idea, or a notification-only post.
Please check post dates before relying on any information in a question or answer.
For follow-up or related questions, please post a new question or idea.
If there is a genuine update to be made, please contact us and request that the post is reopened.

5 replies

fmelizard
Safer
Forum|alt.badge.img+21
  • fmelizardSafer
  • Safer
  • June 5, 2013
Hi,

 

 

This is usually caused by  the compression rate on the writer side ( see format parameters > compress by percentage) and the input data format.

 

I would try to lower the compression rate and see if it results in a less degreaded raster or another output format (jp2) which also support compression.

 

Hope this helps.
C
  • chrisegg
  • Author
  • June 5, 2013
The original ECW files are already compressed, and even though compression rate is set to zero, artifacts still appears in the image. My initial guess is that it's not possible to merge ECW files in FME and write to ECW without degradation.
fmelizard
Safer
Forum|alt.badge.img+21
  • fmelizardSafer
  • Safer
  • June 5, 2013
Compression always results in degradation, so you are right it was already degraded and will be degreaded after mosaiking.
C
  • chrisegg
  • Author
  • June 5, 2013
So how can I create a lossless mosaic of the ECW files?
fmelizard
Safer
Forum|alt.badge.img+21
  • fmelizardSafer
  • Safer
  • June 5, 2013
Write it to a format that doesnt compress , or set the compression to 0, this will result in bigger output features.

Community Stats

32,207
Posts
122,305
Replies
39,891
Members

Latest FME

Terms & ConditionsCookie settingsAccessibility statement
A product of
Safe Software respectfully acknowledges that we live, learn and work on the traditional and unceded territories of the Kwantlen, Katzie, and Semiahmoo First Nations.