How can I control this brightness factor in a conversion?
Below is a zoom-in example: original ecw (left) and resulting geotiff (right)
How to preserve exact colors in raster conversion .ecw to .tiff?
I am converting .ecw files to .tiff and notice that the resulting tiffs are "brighter". In dark areas, this seems to make the tiff look quite different and lower quality.
Userlevel 2
+17
- Contributor
- 7538 replies
-
2 May 2014
Hi,
It's not a direct answer to your question, but there might be a hint to solve the issue.
Geotiff has several compression methods. If you selected a lossy compression method such as JPEG when writing the image, pixel colors might be different from the original data. As well, ECW is also a lossy compression raster format, so pixel colors being displayed on the viewer might be different from pixel values read by the ECW reader depending on both the viewer characteristics and parameter settings of ECW reader.
For your information.
Takashi
Userlevel 4
- 8177 replies
-
2 May 2014
Hi,
could it perhaps be a palette issue. Send both the source and target file to the inspector and check for palette inconsistencies between the rasters.
David
+3
Most likely a colorpallette or rasterbadinterpretation isue(?)
thanks for the hints thusfar.
In looking at this issue further - it seems that using data inspector, the tiff and ecw look identical. Its only when I use ArcGIS do I see the color differences.
It seems that FME is doing something automatcially with display, while ArcGIS needs to be told an extra step? Any ideas?
Reply
Enter your username or e-mail address. We'll send you an e-mail with instructions to reset your password.