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

[Nikos Alexandris]

On Tue, 2010-04-06 at 20:44 +0300, Micha Silver wrote:
> 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.

I 've also thought about that Micha (I was about to suggest Joel to use
less training classes), but I was hesitant to say it :-p

Nikos

> 
> > (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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> >
> >         This mail was received via Mail-SeCure System.
> >
> >
> >          
> >
> >
> >
> >     -- 
> >     Micha Silver
> >     Arava Development Co. +972-52-3665918
> >     http://www.surfaces.co.il
> >
> >
> >
> >
> > This mail was received via Mail-SeCure System.
> 
>