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

[joel dinis]

NO NO NO!

I have 30 CORINE land cover classes to classify.
The number 512, for example, means 5.1.2, is a
nominal number, IS NOT an classe id.

But may be right: may be the way the classes are
represented in the system cause that problem. I'll test
that..


Thanks
JD

On Tue, Apr 6, 2010 at 6:44 PM, Micha Silver <micha at arava.co.il> 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.
>
>  (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
>
>
>
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