06-29-2020 12:15 PM
What is good to export an image from large file size to reduce ? I have two images that are really huge and it can use up space...
06-29-2020 01:06 PM
06-29-2020 02:12 PM
Thanks for the information..
I'm curious ... Is it okay if I re-export to TIFF from ECW to preseve the ratio or is it going to revert to large file size ?
06-30-2020 05:34 AM
The image is going to revert to it’s large file size if you convert from ECW format back to TIFF. If you really want to use the TIFF format you could use LZW or PackBits compression, but neither of these compression methods will come anywhere close to ECW.
06-30-2020 05:37 AM
If you want a lossless compression JPEG 2000 is a good robust technique to use. It also supports lossy if that's the way you want to go.
06-30-2020 09:02 AM
I was able to do export a hillshade into ECW ; however in ArcGIS arcatalog showed me there is two subfiles that it came with it
AllOpacity and Grayscale . The AllOpacity showed me light blue color but the Grayscale looks fine.
Is there a way around to turn the AllOpacity off ?
07-07-2020 10:39 AM
Hi @Robert1968 ,
As far as I know ERDAS IMAGINE always create the opacity channel when creating ECW v3 files. You almost always need it because ECW is a lossy compression so "background" generally becomes "not background" and the opacity channel is used to re-mask that. It also takes up virtually no additional space because it's only 1-bit (and losslessly compressed).
Is the opactiy channel causing a problem?