s.surf.tps parameter values

[Martin Ameskamp]

> Martin use lower tension (in relatively flat terrain it should be
> much lower than the values suggested in the manual) and use smoothing to
> avoid overshoots. Smoothing effect for e.g. sm=0.1 is usually much smaller
> than the accuracy of data and allows you to use  low tension.
> We have a new radial basis function which makes it easier to use lower
> tension, however we don't have time and worksforce to implement it now,
> so you really have to fiddle with parameters to get it right.

        Helena,

        thanks very much for your reply. Actually, we did the terrain
        modelling last year and I probably won't have the time to do
        it again, but we did use tension values around 60-100 and
        smoothing around 0.1 - 0.01.

        The terrain is fairly flat (undulating glacial till between
        25m and 55m) and we represent it in cm's in order to get
        any detail (this will all be a lot better in 4.2, I understand...)

        On another track - I'm currently trying out SG3d for visualization
        of some of the results from my nearly complete PhD Thesis, which
        is all about 3d continous soil models (our central computing
        centre recently acquired two Silicon Graphics machines with the
        necessary hardware). While I find this very interesting and helpful,
        the SG4d program mentioned in some of the visualisation Web
        pages sounds even better - is any information available on that?

        Thanks very much in advance,  Martin