[R] [R-sig-Geo] Follow up: surfaces and digital terrain model

[Renaud Lancelot]

2007/5/31, Prof Brian Ripley <ripley at stats.ox.ac.uk>:
> I believe you are looking for the function contourLines() in package
> graphics.
>
> At some point in the intervening years there was a clines package on CRAN,
> and if you know that you can find it at
> http://cran.r-project.org/src/contrib/Archive/C/clines_2.0-2.tar.gz
> That confirms it has been superseded by contourLines.
>
> BTW, it is Paul Murrell (two l's) we have to thank for this.

Yes, indeed :-)

Renaud


>
>
> On Thu, 31 May 2007, Andrew Niccolai wrote:
>
> > I realize that as of yesterday, this message thread is 4 years old but can
> > someone possibly post the clines function that Renaud mentions in the
> > posting below?  That would be wonderful and most appreciated.
> >
> > Thanks,
> > Andrew
> >
> >
> > Andrew Niccolai
> > Doctoral Candidate
> > Yale School of Forestry
> >
> >
> >
> > From: Renaud Lancelot <lancelot>
> > Date: Fri May 30 22:37:02 2003
> >
> > Yesterday, I posted the following:
> >
> >>> I have computed a digital terrain model from a set of points (x, y, z)
> >>> using the function interp() in package akima. I want to predict flooded
> >>> surfaces given target values of z. I can display the flooded surfaces
> >>> with contour() or image(), but I don't know how to get the polygons
> >>> delimiting the surfaces. Did anyone write a function for this purpose ?
> >
> > Many thanks to Roger Bivand, Paul Murrel, Deepayan Sarkar, Barry
> > Rowlingson and Thomas W Blackwell for their replies and their help. Paul
> > Murrel provided me with a function "clines", kindly ported to Windows by
> > Duncan Murdoch. This function does exactly what I need, i.e. it returns
> > a list of polygons corresponding to target value(s) of z.
> >
> > I wrote a function to compute (hopefully !) what I want, i.e. predicted
> > flooded surfaces given target values of z (managing the cases of several
> > independent watered surfaces, possibly with islands). Provided that Paul
> > Murrel agrees to share his function, I will be happy to send it to
> > anyone wishing to use and improve it (and debug it ;-) ).
> >
> > Best regards and thanks again,
> >
> > Renaud
> >
> >
>
> --
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>
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>


-- 
Renaud LANCELOT
Département Systèmes Biologiques du CIRAD
CIRAD, Biological Systems Department

Campus International de Baillarguet
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