[GRASS-dev] reg i.pca module

[Rashad M]

Hi

As mentioned in wiki does the output pixel = eigenvector * input pixel?


On Thu, Feb 7, 2013 at 10:59 AM, Rashad M <mohammedrashadkm at gmail.com>wrote:

> Thanks Nikos and Mortiz,
>
> From GRASS Wiki what I got is I need more details of step.6 in the
> Background section
> i.e *project original dataset signals* (PC's or PC scores: eigenvector *
> input-data) to get
>
> projecting the dataset is based on the text output of i.pca eigen values
> and input data.
>
> I guess there must be a simple transformation equation that can be applied
> to every pixel in the input data to get the raster output of i.pca.
>
> Nikos, Your thesis is a long read and I only need a very small part from
> it. If you could tell me those( I strongly believe you can ) then it will
> be great. I need to start coding after this and this is only a small part
> of it. my actual work is pure pixel identification for spectral unmixing
>
>
> On Thu, Feb 7, 2013 at 5:43 AM, Nikos Alexandris <nik at nikosalexandris.net>wrote:
>
>> Rashad M wrote:
>>
>> > > Hi All,
>>
>> > > i.pca outputs raster bands and the pixel values are transformed
>> > > obivously. But anyone can tell me how the transformation works
>>
>> > > if a pixel P1 has value X after i.pca it will be Y
>>
>> > > Is there any specific math equation that is applied to every pixel by
>> PCA?
>>
>> Moritz Lennert wrote:
>>
>> > http://en.wikipedia.org/wiki/Principal_component_analysis
>> > and
>> > http://grasswiki.osgeo.org/wiki/Principal_Component_Analysis
>>
>> Ehm, right --  I've overlooked your post Moritz, apologies.
>>
>> Nikos
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>
>
>
> --
> Regards,
>    Rashad
>



-- 
Regards,
   Rashad
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