Global Mapper v25.0

Quality of exported GeoTIFF image

Lukar
Lukar Global Mapper User
edited April 2009 in Raster Data
Hi everybody,

Is it possible to increase visual kvality of exported reprojected image in GeoTIFF format?
Visual quality of reprojection on the screen in GM is quite a good, but exported image opened in any graphic editor is more distorted and it is difficult to use it.. F.g. some of names in the map are difficult to read.
Can I change resampling method at exporting, or at projecting image?

Thanks.

Comments

  • global_mapper
    global_mapper Administrator
    edited June 2008
    You can enable interpolation for the image prior to reprojecting and exporting by opening the Control Center, selecting the image, pressing Options, then checking the box for anti-aliasing (interpolation). Then when you export bilinear interpolation will be used to generate new samples rather than nearest neighbor.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • Lukar
    Lukar Global Mapper User
    edited June 2008
    Thanks, that's it! My problem is solved.
  • TSchneider
    TSchneider Global Mapper User
    edited April 2009
    Hello

    Does the same aply for exporting ECW?

    I wonder if there is a quality difference between exporting to TIFF or ECW?
    Standard compression for ECW is 1:10. Is that mostly used or should we alter to 1:1 in order to increase export quality? FYI, the source image is google sat material 9200x9200 Pixel 96 DPI 24bit bitmap.


    sincerely
    Tobi
  • global_mapper
    global_mapper Administrator
    edited April 2009
    Tobi,

    Yes, you will still likely want to enable interpolation when exporting ECW files to avoid the "nearest neighbor shift" issue.

    You should consider the ECW quality setting separate from this issue. By default GeoTIFF files are lossless (with JPEG-in-TIFF being the exception), but they are also many times larger than ECW files. Unless you absolutely require no loss, then going with 10 or even 20:1 compression for an ECW file should still be very good and your files will be much smaller.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com