[gdal-dev] Heuristics to classify raster data ?

Even Rouault even.rouault at mines-paris.org
Thu Mar 6 11:19:30 PST 2014


Hi,

I'd be interested in an algorithm to automate the classification of raster data 
between maps (let's say rendering of OpenStreetMap data, or other digital 
maps) one one side and aerial/satellite imagery on the other side, without 
looking at metadata (bare geotiff typically). This is to help in automating 
bulk of import of data from a media and establishing a first level of 
classification.

Has anyone already done that and has code and/or advice to share, or know a 
software project that would do that ?

Some ideas that came to my mind :
- maps have typically a much more reduce number of colors than imagery, but 
you may have imagery that has already been transformed to 256 colors to reduce 
storage space.
- maps have generally a majority color (e.g. white, green), but not in all 
zones (urban zones will have more features)
- maps have higher spatial frequency (lines, text) whereas imagery will be 
more continuous : use of gradient, and compute statistics on it ?

Even

-- 
Geospatial professional services
http://even.rouault.free.fr/services.html


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