Mosaicing ECW without degradation

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.

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.

Compression always results in degradation, so you are right it was already degraded and will be degreaded after mosaiking.

So how can I create a lossless mosaic of the ECW files?

Write it to a format that doesnt compress , or set the compression to 0, this will result in bigger output features.