[GRASS-user] Re: [GRASS-dev] i.pca

[Brad Douglas]

On Fri, 2007-02-23 at 11:20 -0800, Dylan Beaudette wrote:
> On Monday 19 February 2007 14:59, Brad Douglas wrote:
> > Hello,
> >
> > I just committed a rewritten i.pca module.  It now supports NULL cells
> > without skewing the data and will work properly with float/double maps.
> > It's a bit slower than the original, but that's the price we pay for
> > modules that work. :-)
> >
> > My testing has proved good results, but I'd like to have others test.
> 
> Hi Brad,
> 
> I just tried it out with some ikonos imagery (r,g,b bands only...) with good 
> results. The various vegetation communities standout, along with the rock 
> outcroppings (bright pink) ! I have previously been using NDVI for the rock 
> outcrops, but it looks like this approach might work better. Good 
> performance, total time for 13838448 cells was about 1 minute on a 3ghz xeon. 

Thank you guys for doing a little testing for me!


-- 
Brad Douglas <rez touchofmadness com>                    KB8UYR/6
Address: 37.493,-121.924 / WGS84    National Map Corps #TNMC-3785