Nair, Murlidharan T <mnair <at> iusb.edu> writes: > > Alex Brenning, the developer of the RSAGA package told me that and I quote > "the RSAGA package (which uses functions from the free geographical > information system [GIS] SAGA GIS) has a curvature function that is designed > to calculate the curvature of surfaces, in particular raster (i.e. gridded) > digital elevation models. I am not aware of a function in SAGA GIS or other > GIS that would calculate curvatures along a line, especially not in 3D"
I have difficulties seeing how you would go about to do this. A surface locally is characterized by two main curvatures --- this is Gauss' theorem for 2-dim geometry. The sphere has the same curvature, 1/r, in both directions. So maybe you can approximate the surface by an ellipsoid, but a strange one as the main directions may not be orthogonal. I am not sure this is what you wanted to achieve. As a side remark: The circle approximating a curve in three dimensions is not uniquely determined. Regards Hans Werner > I shall try to develop it and if I am successful I shall make it available. > > Cheers../Murli > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
