[FWTools] gdal translate - air photo seems washed out after converting image

Mark Volz MarkVolz at co.lyon.mn.us
Wed Jul 10 16:08:14 EST 2013


I converted a mr sid air photo to a tif file.  The colors appear washed out and too bright compared to the mr sid file. 

I would like to create an image file that has the following three characteristics:

1) Fast for Mapserver to read.
2) Relatively the same size as the MrSID file.  - I would prefer a file size that is no larger than twice the size of the Mr SID file, even if it means that I have to take a small hit by using compression
3) retains the same image quality as the original MrSID file

The following two commands made the image fast for mapserver, and relatively small.  But the colors were washed out...

c:\ms4w\apps\PipestoneMaps\Raster\Picto2013>gdal_translate -CO TILED=YES -CO PHOTOMETRIC=YCBCR -CO TFW=YES -CO COMPRESS=JPEG -CO BIGTIFF=YES MNPIPE13-SID-9INCH.sid New.tif
c:\ms4w\apps\PipestoneMaps\Raster\Picto2013>gdaladdo -r average --config compress_overview JPEG --config photometric_overview YCBCR New.tif 2 4 8 16 32 64 128 256

What can I do to improve the image quality, while retaining the speed and a moderate file size?


Mark Volz, GISP
GIS Specialist

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