exporting world wind tiles

ChipootleChipootle Global Mapper UserPosts: 9
edited March 2010 in Raster Data
Hello, I seem to be getting "grainy" tiles when using global mapper to export aerial imagery in world wind format.

I exported the exact same geotiff using global mapper and another program called dstile using identical level zero tile size and both in jpg format. Here is how it looks.

The end of lvl0 - Global Mapper
gmlvl0end.jpg

The end of lvl0 - Dstile
dstlvl0end.jpg


The start of lvl1 - Global Mapper
gmlvl1start.jpg

The start of lvl1 - Dstile
dstlvl1start.jpg

When I exam the exact same tile produced by both programs, they seem to be identical, except when I view it in world wind. Is there a setting that I am perhaps using incorrectly?

Comments

  • MattMatt Global Mapper User Posts: 176Trusted User
    edited March 2010
    Mike may have better answer, but looks like dstile is smoothing or using anti-aliasing. Detail in imagery looks to be the same. I think GM version looks better even.
  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited March 2010
    I agree this is likely a result of what resampling method is used. You can control the resampling method used in Global Mapper on the Options dialog for a layer. Try enabling bilinear or bicubic interpolation to see if that improves the result at all. Actually if you have v11.02 and haven't disabled automatic export interpolation you are likely already getting some interpolation for the down-sampled zoom levels.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • ChipootleChipootle Global Mapper User Posts: 9
    edited March 2010
    Thanks for the reply.

    As it turns out, it wasn't global mapper at all :).

    It was an internal field of view setting that was causing the problem.
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