[Gdal-dev] How to extract sub-image

[Norman Vine]

Clay, Bruce writes:
> 
> I know how to open a file and read the bands and thus the data so I can
> get data for a sub-image but I don't see how to create a file of the
> same format that is a particular sub-image of the overall image.
> Actually this would be a subset of GTOPO30 data but I believe that is
> treated the same as an actual image.
> 
> Since this seems to be a very common function, I was wondering if there
> isn't already a tool written to do this.  That is a not Python tool.

see the manpage for gdal_translate 

esp..

 -srcwin xoff yoff xsize ysize:
    Selects a subwindow from the source image for copying based on pixel/line location. 
-projwin ulx uly lrx lry:
    Selects a subwindow from the source image for copying (like -srcwin) 
    but with the corners given in georeferenced coordinates.

but ...

FWIW - I suggest you take a couple of hours and learn Python as it 
exposes a lot of GDAL functionality in a *very* easy to use way  :-)

http://www.python.org/topics/learn/prog.html

Norman