how to cut a big raster gis

[Matthew Perry]

Leopold,
 
On 8/24/05, Leopold Schefcik (MULTIMEDIAPLAN.AT)
<leopold.schefcik at multimediaplan.at> wrote:
> How can I cut a big raster gis (satellite picture) to many small ones with
> different quality for different zoom factors?
> 

The best way to deal with large rasters at multiple zoom levels is to
create overviews (aka pyramids) using the gdaladdo utility that comes
with gdal. These are essentially reduced resolution versions of the
original image stored in a single file. When mapserver accesses the
raster, it will use the overview "layers" depending on the scale of
the image, reducing the need to resample on the fly. This speeds
things up immensely if you have rasters that are being viewed at
widely variable scales.

check out http://gdal.maptools.org/gdal_utilities.html#gdaladdo for the details.
-- 
Matt Perry
perrygeo at gmail.com
http://www.perrygeo.net