[GRASS-user] Calculating eigen values and%varianceexplainedafter PCA analysis

Nikos Alexandris nikos.alexandris at felis.uni-freiburg.de
Tue Mar 3 02:06:53 EST 2009

> I got the svn grass6_devel code from the location you suggested and have
> now installed but with lots of errors. Here is the output from the
> 'make' command (see below the lapack.h error). I understand that I need
> to cd into the directory where the error occurred and run make inside
> that directory. I do this for the gmath directory and I once again
> receive an error message related to the lapack.h file. The same error
> occurs when running make in other error locations.

> /usr/local/src/grass6_devel/dist.i686-pc-linux-gnu/include/grass/lapack.h:5144:
> error: expected declaration specifiers or ‘...’ before ‘ftnlen’
> make: *** [OBJ.i686-pc-linux-gnu/del2g.o] Error 1


what are the exact steps you are executing in order to compile

(assuming you work under linux) If you already had done a compilation
before, did you "make distclean" before re-compiling?
(or "sudo make distclean").

> I dont have much more time to spend on this so would ideally just like
> to get the i.pca working in development installation so that I can use
> i.pca and get the variance and eigen values. In my tests run so far I
> have seen that i.pca produces more realistic results, based on
> qualitative assessment. As such, I will use i.pca instead of the
> 'by-hand-method'

If you don't mind to share some more info about the way you assess the
quality of the components (just even mentioning some will be great - I
am really interested in it).

> Thanks for all your help wrt running pca in grass.
> Wesley

Thanks to the community and Hamish for his time.

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