[R] Follow up: surfaces and digital terrain model
Prof Brian Ripley
ripley at stats.ox.ac.uk
Thu May 31 23:34:34 CEST 2007
I believe you are looking for the function contourLines() in package
At some point in the intervening years there was a clines package on CRAN,
and if you know that you can find it at
That confirms it has been superseded by contourLines.
BTW, it is Paul Murrell (two l's) we have to thank for this.
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.
> 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,
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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