[R] Contour Plots

[Uwe Ligges]

Bernard L. Dillard wrote:

> Hello all.
> 
> I'm confused a bit about contour plots.  After reading the help at
> "?contour", it seems as though the contour plot is for 3D plots (x,y, and
> z).  My data is in the form of grid coordinates (x,y), and I want to see a
> contour plot of the data so that I can tell where most observations lie. 
> My question is simple but still evasive.
> 
> Say my data is called places.  One column is X and another is Y.  Or,
> 
>                   places$X          places$Y
> 
> Coordinate 1          32               50
> Coordinate 2          15               33
> Coordinate 3          28               20
> etc
> 
> How do I get R to do the contour plot with no third "z" coordinate?

For just 2 columns, a contour plot does not make much sense, I guess.
I think an image() makes much more sense in this case.

Your z matrix consists of the entries of the data.frame/matrix given 
above, the x and y vectors are the column and row numbers.


Uwe Ligges



> Thanks.
>