[Cartoweb-users] OT:tools for image processing

[Jacolin Yves]

Hi,

You can use grass and process a raster difference between both 
georeferentiated ortophotos (with r.mapcalc) then you will obtain an another 
raster which you can process to filter data in binary format (0-1 only 1 
means same values, 1 values are different) using r.reclass function. So you 
can vectorise this raster into polygon vector r.to.vect.

I think you should optimize this process as I have never tested it before.

It is free as free mind and free beer :) Try using QGIS with the nice grass 
plugin.

Regards,

Y.
Le Friday 10 August 2007 02:17:41 giuseppe.derossi at email.it, vous avez écrit :
> hi all,
> Is there a software tool (or php/java/c++ apis) which compares two
> georeferentiated ortophotos and retuns a shape (shp,shx,dbf) which contain
> the polygons which have the major differences beetwen the two photos? if
> free the better :-)
>
> Giu
>
> Sorry for the OT
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-- 
Yves Jacolin
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