R help - May 2009 - contour lines on persp plot

Hello folks,

I am a beginner R user. I have been able to make a 3D surface plot using
'persp'. The surface is made by a grid of lines emanating
perpendicularly
from each of the x and y axes at regular intervals.

I can get rid of that grid by setting 'border=NA'.

Can anyone suggest some ways to replace the grid with contour lines, to
create a 3-dimensional contour map?

Thanks for any help.

Here is an example of what I have so far:

#to create a perspective plot; plots funct. across all combos of x and y

fn<-function(x,y){sin(x)+2*y} #this looks like a corrugated tin roof

x<-seq(from=1,to=100,by=1) #generates a list of x values to sample
y<-seq(from=1,to=100,by=1) #generates a list of y values to sample

z<-outer(x,y,FUN=fn) #applies the funct. across the combos of x and y

persp(z,col='lightgray',shade=.5,border=NA,) #plots without gridlines

One quick idea is to use the functions

- contourLines() to calculate the contour lines
- trans3d() to transform the 3D coordinates into the 2D space you will 
be plotting into
- polygon() to plot the contour lines

Uwe Ligges




Jack Siegrist wrote:
> Hello folks,
> 
> I am a beginner R user. I have been able to make a 3D surface plot using
> 'persp'. The surface is made by a grid of lines emanating
perpendicularly
> from each of the x and y axes at regular intervals.
> 
> I can get rid of that grid by setting 'border=NA'.
> 
> Can anyone suggest some ways to replace the grid with contour lines, to
> create a 3-dimensional contour map?
> 
> Thanks for any help.
> 
> Here is an example of what I have so far:
> 
> #to create a perspective plot; plots funct. across all combos of x and y
> 
> fn<-function(x,y){sin(x)+2*y} #this looks like a corrugated tin roof
> 
> x<-seq(from=1,to=100,by=1) #generates a list of x values to sample
> y<-seq(from=1,to=100,by=1) #generates a list of y values to sample
> 
> z<-outer(x,y,FUN=fn) #applies the funct. across the combos of x and y
> 
> persp(z,col='lightgray',shade=.5,border=NA,) #plots without
gridlines
> 
> ______________________________________________
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http://www.R-project.org/posting-guide.html
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