R help - Oct 2004 - Plotting a 3D surface

Hi 

Does R have a function or has someone written a function to draw a 3d
surface from a scatter plot of values using either ksmooth or locpoly. OR a
transform function a that merges x relation z and y relation z to (x,y)
relation z?  

I tried out scatterplot3d but it seems it would take a bit of work to get
scatterplot3d to draw a curved surface.


Lawrence

On Wed, 20 Oct 2004 08:18:10 -0400, "lawrence Perepolkin"
<lperepol at necessity.org> wrote :
>Hi 
>
>Does R have a function or has someone written a function to draw a 3d
>surface from a scatter plot of values using either ksmooth or locpoly. OR a
>transform function a that merges x relation z and y relation z to (x,y)
>relation z?  
>
>I tried out scatterplot3d but it seems it would take a bit of work to get
>scatterplot3d to draw a curved surface.
persp() or functions in the rgl package can draw the curved surface,
but you'll need to calculate it yourself first.  You should fit a
model to the surface then use predict to find the predictions at every
grid point; that's the sort of data that persp() wants.  As far as I
know both ksmooth and locpoly are one dimensional scatterplot
smoothers, but other functions (e.g. gam() in mgcv) can do higher
dimensional smoothing.

Duncan murdoch

Dear Lawrence,

You might take a look at the scatter3d function in the Rcmdr package, which
uses the rgl package. scatter3d() includes some smoothing, but not by
ksmooth() or locpoly(), so you might have to alter it for your purposes, but
that shouldn't be hard.

I hope that this helps,
 John

--------------------------------
John Fox
Department of Sociology
McMaster University
Hamilton, Ontario
Canada L8S 4M4
905-525-9140x23604
http://socserv.mcmaster.ca/jfox 
-------------------------------- 
> -----Original Message-----
> From: r-help-bounces at stat.math.ethz.ch 
> [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of 
> lawrence Perepolkin
> Sent: Wednesday, October 20, 2004 7:18 AM
> To: R-help at stat.math.ethz.ch
> Subject: [R] Plotting a 3D surface 
> 
> Hi 
> 
> Does R have a function or has someone written a function to 
> draw a 3d surface from a scatter plot of values using either 
> ksmooth or locpoly. OR a transform function a that merges x 
> relation z and y relation z to (x,y) relation z?  
> 
> I tried out scatterplot3d but it seems it would take a bit of 
> work to get scatterplot3d to draw a curved surface.
> 
> 
> Lawrence
> 
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