[GRASS-user] Orthophotos in .sid - removing black border

[Hamish]

Hamish wrote:
> I may be dreaming, but I seem to remember writing a script to do that
> some time ago (maybe March?) to crop the blank edges off the NOAA BSB
> format nautical charts. try searching the archives and wiki.
> 
> see also the image classification modules, r.mask, and "g.region zoom=".


nope, not dreaming. see attached.

you'll have to adjust it to suit your needs, but the method works,
especially if the collars are square to the image bounds.

otherwise open the image in GIMP or whatever, use the magic wand select
on the border, set it to 0:0:0 or 255:255:255, reapply georef with
gdal_translate, reimport with r.in.gdal, use r.null to remove 0:0:0 or
255:255:255.


Hamish



      
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