[GRASS-user] Extracting grey features from an image

baobazz baobazz at hotmail.fr
Thu May 27 05:59:00 EDT 2010


Hello 

I've got a black and white image with some grey features on it 

I'd like to create a new image containing only these features so I can
vectorize them

i think that I have to use
r.mask
r.mapcalc
or
r.reclass

r.describe raster
returns me
0-121 123 125-127 132-255

I created a mask of my image 
r.mask input=image maskcats="0 thru 121" -i
-i to invert the maskcats range

Only the grey features appear.

So, my grey features seem to have the 0-121 range category of values.

Considering that, how can I manage to create a raster map based only on
these values.

I used r.reclass like this:
r.reclass input=raster output=rasterRec
>0 thru 121=1 black
>*=NULL
But I didn't get any good result...

Any help would be greatly appreciated!



-- 
View this message in context: http://osgeo-org.1803224.n2.nabble.com/Extracting-grey-features-from-an-image-tp5107822p5107822.html
Sent from the Grass - Users mailing list archive at Nabble.com.


More information about the grass-user mailing list