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Bug in elevation grid conversion ?

eranb burstaineranb burstain Global Mapper UserPosts: 2
edited December 2010 in Bug Report
Hi !
I'm loading a Dted elevation file (.dt0) and exporting it as a geotiff elevation file.
In GM itself it looks fine (both files are identical) but using gdalinfo the origin of the files have an offset of 1/2 sample.
furthermore, if I use gdaltranslate to convert dted to geotiff and load both in GM, there is an offset in the grid.
(GM 12,gdal 1.7.2 or 1.6)

Comments

  • global_mapperglobal_mapper Administrator Posts: 17,238
    edited December 2010
    I wonder if GDAL is mis-interpreting the origin coordinates in the DTED files. They should be treated as 'pixel-is-point' with the origin being the center of the bottom-left sample, not the bottom-left corner of the lower left sample. This allows for the edge rows and columns of samples to overlap with adjacent DTED tiles as the DTED specification specified.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • eranb burstaineranb burstain Global Mapper User Posts: 2
    edited December 2010
    tnx, i see now that it's a bug in gdal :
    http://trac.osgeo.org/gdal/wiki/rfc33_gtiff_pixelispoint

    eran.
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