Nikos Alexandris wrote: > Edzer: > > I do worry about the wiki that states results are "similar" between R and >> grass, when the differences appear e.g. in the third or second digit of a >> loading (eigenvector value). Clearly something is is going on, here. >> > > So you think it's really important? Isn't it a matter of pixel-inclusion > in the various algorithms/programs? > Well, it's just much larger than I could imaging numerical dispersion would give; if you mean by pixel-inclusion different methods how missing values are treated, then I can understand it a bit better, given that there are substantial amounts of them. The wiki might mention this possibility. (Although I don't see why grass wouldn't ignore partially missing valued pixels)
Note that I didn't run the examples, I was just surprised. When I compare different software implementations of an algorithm, I usually don't stop worrying until differences happen beyond digit 5. -- Edzer Pebesma Institute for Geoinformatics (ifgi), University of Münster Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251 8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de/ http://www.springer.com/978-0-387-78170-9 [email protected] _______________________________________________ grass-stats mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-stats
