On Tue, Mar 26, 2013 at 2:44 PM, Markus Metz <[email protected]>wrote:
> On Tue, Mar 26, 2013 at 8:39 AM, Rashad M <[email protected]> > wrote: > > Hi, > > > > i.pca creates 6 raster maps for 6 input raster > > > > eg: > > > > i.pca > > > in=lsat7_2002_10,lsat7_2002_20,lsat7_2002_30,lsat7_2002_40,lsat7_2002_50,lsat7_2002_70 > > \ > > out=lsat7_2002_pca > > > > > > I have a doubt here > > > > Does the output lsat7_2002_pca.1 is the corresponding map for > lsat7_2002_10? > > No. lsat7_2002_pca.1 contains the principal component with the highest > eigenvalue and is calculated using all input bands. More generally, > each lsat7_2002_pca.* map is calculated using all input bands. Look at > the eigenvectors to find out the weights with which each input map > contributes to a specific PCA. > > So by knowing a pixel value of lsat7_2002_pca.1 can I get the value before transformation in PCA. consider this: I have two bands B1,B2 and after i.pca I get PC1,PC2. Then is there a way to derive value of X,Y where X belongs to B1 and Y belongs to B2 by only knowing P,Q where P belongs to PC1 and Q belongs to PC2 and also X,Y and P,Q are of same index (row,col) I hope this is clear > Markus M > > > > > If so the lsat7_2002_10_pca.1 contains PCA transformed pixel for > > lsat7_2002_10 > > > > Is this correct? > > > > -- > > Regards, > > Rashad > > > > _______________________________________________ > > grass-dev mailing list > > [email protected] > > http://lists.osgeo.org/mailman/listinfo/grass-dev > -- Regards, Rashad
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