[GRASS-user] A problem with i.gensigset.

[Micha Silver]

joel dinis wrote:

> Hello Micha,
>
> I put r.info <http://r.info/> -r amostras
> as sugested, get the following:
> min=112
> max=512
>
So, if I understand correctly, you are trying to classify into 400 
separate classes?!
I'm a beginner with image classification, and others with more 
experience will know better, but I'll bet that's your problem. There 
must be many separate training areas (with different cat values) with a 
very similar spectral signature, and the algorithm is not able to 
differentiate between them.

> (This values are index to my classes.)
>
> JD
>
> On Tue, Apr 6, 2010 at 4:39 PM, Micha Silver <micha at arava.co.il 
> <mailto:micha at arava.co.il>> wrote:
>
>     Nikos Alexandris wrote:
>
>         (sorry for re-sorting the message, just to keep it easy to
>         follow-up)
>
>         joel dinis:
>          
>
>                    > I trying to classify remote sensing imagery, and
>                    > I thought to try the i.smap module, but
>                    > when I run the i.gensigset,
>                
>
>
>         Nikos Alexandris:
>          
>
>                    Please, could you copy-paste the exact command you
>             used?
>                    Does the "maxsig=" (e.g. maxsig=20) make any
>             difference?
>                
>
>
>         joel dinis:
>
>          
>
>             In fact, I put maxsig=30.
>             i.gensigset trainingmap=amostras group=grupo subgroup=subgrupo
>             signaturefile=assinaturas maxsig=30
>                
>
>
>         What about smaller maxsig's, like:
>
>         - maxsig=25
>         - maxsig=20
>         - maxsig=15
>
>         ?
>
>         Nikos
>
>          
>
>     Also it might help to know what is contained in the trainingmap. i.e:
>     r.info <http://r.info> -r amostras
>
>          
>
>                            >  I always
>                    > get the same problem:
>                    > ...
>                    > Removed a singular subsignature number 1 (9 remain)
>                    > Removed a singular subsignature number 1 (8 remain)
>                    > Removed a singular subsignature number 1 (7 remain)
>                    > Removed a singular subsignature number 1 (6 remain)
>                    > Removed a singular subsignature number 1 (5 remain)
>                    > Removed a singular subsignature number 1 (4 remain)
>                    > Removed a singular subsignature number 1 (3 remain)
>                    > Removed a singular subsignature number 1 (2 remain)
>                    > Removed a singular subsignature number 1 (1 remain)
>                    > Unreliable clustering. Try a smaller initial
>             number of
>                    clusters
>                    > Removed a singular subsignature number 1 (-1 remain)
>                    > Unreliable clustering. Try a smaller initial
>             number of
>                    clusters
>                    > Number of subclasses is 0
>                    > Clustering class 12 (184 pixels)...
>                    > Removed a singular subsignature number 1 (9 remain)
>                    > Removed a singular subsignature number 1 (8 remain)
>                    > Removed a singular subsignature number 1 (7 remain)
>                    > Removed a singular subsignature number 1 (6 remain)
>                    > Removed a singular subsignature number 1 (5 remain)
>                    > Removed a singular subsignature number 1 (4 remain)
>                    > Removed a singular subsignature number 1 (3 remain)
>                    > Removed a singular subsignature number 1 (2 remain)
>                    > Removed a singular subsignature number 1 (1 remain)
>                    > Unreliable clustering. Try a smaller initial
>             number of
>                    clusters
>                    > Removed a singular subsignature number 1 (-1 remain)
>                    > Unreliable clustering. Try a smaller initial
>             number of
>                    clusters
>                    > Number of subclasses is 0
>                    > i.gensigset complete.
>                    >
>                    > And afterwards the signature file doesn't have any
>                    > spectral information. I really don't understand whats
>                    happening
>                    > and the cause to this outcome.
>                    >
>                    > Can anyone solve this "enigma"?
>                    >
>                    > Ps: I don't know if this information is important: I
>                    collected
>                    > about 450 samples distributed by 10 classes. I
>             may also
>                    > add that the average number of pixels per sample
>             is around
>                    50.
>                    >
>                    > And thanks list, for the previous tips: they were
>             very
>                    useful.
>                
>
>
>
>
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>
>          
>
>
>
>     -- 
>     Micha Silver
>     Arava Development Co. +972-52-3665918
>     http://www.surfaces.co.il
>
>
>
>
> This mail was received via Mail-SeCure System.


-- 
Micha Silver
Arava Development Co. +972-52-3665918
http://www.surfaces.co.il