>From the code: result = (nirchan - (greenchan - (bluechan - redchan)))/(nirchan - (greenchan - (bluechan + redchan)));
On 10 October 2013 00:07, GRASS GIS <[email protected]> wrote: > #2098: i.vi gari wrong formula? > > -----------------------+---------------------------------------------------- > Reporter: kristinah | Owner: grass-dev@… > Type: defect | Status: new > Priority: normal | Milestone: 6.4.4 > Component: Default | Version: unspecified > Keywords: | Platform: Unspecified > Cpu: All | > > -----------------------+---------------------------------------------------- > The formula for GARI in the manual > (http://grass.osgeo.org/grass70/manuals/i.vi.html) seems to be wrong. As > it is now, the result would always be 1. > > It is > " > GARI = ( nirchan - (greenchan-(bluechan - redchan))) / > ( nirchan- (greenchan-(bluechan - redchan))) > " > > It should be (e.g. according to > http://www.indexdatabase.de/db/i-single.php?id=363) > " > GARI = ( nirchan - (greenchan-(bluechan - redchan))) / > ( nirchan- (greenchan+(bluechan - redchan))) > " > > As the formula in the manual seems to be taken from code, the code might > be wrong as well. I did not test the function, only read the manual > online. > > -- > Ticket URL: <https://trac.osgeo.org/grass/ticket/2098> > GRASS GIS <http://grass.osgeo.org> > > _______________________________________________ > grass-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-dev -- ----
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