Hey, R-listers Now I am going to estimate or approximate a surface in 3-D space given a large enough number of (x,y,z) data sets. So for these 3-D data points, is it possible to get a surface function, like z=f(x,y) to represent this underlying surface? Thanks for your time and point. Fred
Hi On 3 Mar 2003 at 22:03, Feng Zhang wrote:> Hey, R-listers > > Now I am going to estimate or approximate a surface in > 3-D space given a large enough number of (x,y,z) data sets. > > So for these 3-D data points, is it possible to get a surface > function, like z=f(x,y) to represent this underlying surface?I am not sure but interp from akima package shall give you an interpolation of your data.> > Thanks for your time and point. > > Fred > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > http://www.stat.math.ethz.ch/mailman/listinfo/r-helpCheers Petr Pikal petr.pikal at precheza.cz p.pik at volny.cz
Have you tried looking at packages mgcv or gss?> Now I am going to estimate or approximate a surface in > 3-D space given a large enough number of (x,y,z) data sets. > > So for these 3-D data points, is it possible to get a surface > function, like z=f(x,y) to represent this underlying surface?Simon _____________________________________________________________________> Simon Wood simon at stats.gla.ac.uk www.stats.gla.ac.uk/~simon/ >> Department of Statistics, University of Glasgow, Glasgow, G12 8QQ >>> Direct telephone: (0)141 330 4530 Fax: (0)141 330 4814
Locfit has worked well for me. http://cm.bell-labs.com/cm/ms/departments/sia/project/locfit/ Stuart Dr Stuart Leask MA MRCPsych, Clinical Lecturer in Psychiatry University of Nottingham Dept of Psychiatry, Duncan Macmillan House Porchester Road, Nottingham. NG3 6AA. UK http://www.nottingham.ac.uk/psychiatry/staff/sjl.html ----- Original Message ----- From: "Simon Wood" <simon at stats.gla.ac.uk> To: "Feng Zhang" <f0z6305 at labs.tamu.edu> Cc: "R-Help" <r-help at stat.math.ethz.ch> Sent: Tuesday, March 04, 2003 9:55 AM Subject: Re: [R] How to estimate or approximate a 3-D surface> Have you tried looking at packages mgcv or gss? > > > Now I am going to estimate or approximate a surface in > > 3-D space given a large enough number of (x,y,z) data sets. > > > > So for these 3-D data points, is it possible to get a surface > > function, like z=f(x,y) to represent this underlying surface? > > Simon > _____________________________________________________________________ > > Simon Wood simon at stats.gla.ac.uk www.stats.gla.ac.uk/~simon/ > >> Department of Statistics, University of Glasgow, Glasgow, G12 8QQ > >>> Direct telephone: (0)141 330 4530 Fax: (0)141 330 4814 > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > http://www.stat.math.ethz.ch/mailman/listinfo/r-help
ripley@stats.ox.ac.uk
2003-Mar-04 11:42 UTC
[R] How to estimate or approximate a 3-D surface
On Tue, 4 Mar 2003, Stuart Leask wrote:> Locfit has worked well for me. > http://cm.bell-labs.com/cm/ms/departments/sia/project/locfit/Unfortunately it has not been updated for current versions of R: it also writes diagnostic output to stderr which is not shown on GUI versions of R (especially on Windows). There is a version in the Devel area on CRAN. Package akima is the most obvious choice for interpolation. For smoothing, there are all the various spatial packages (and package fields) as well as mgcv and gss already mentioned. -- 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