[R] Contour plot on a triangular mesh

[Jason Edgecombe]

I'm not sure if this is appropriate. If the sum of your variables is 
always the same constant, then you might try a Ternary plot ( 
http://en.wikipedia.org/wiki/Ternary_plot ).

The "vcd" package can make ternary plots.

On 01/20/2012 02:56 PM, Roary wrote:
> I have two observed categorical variables X1 and X2, with X3=X1+X2, and a
> continuous response Y. I can interpolate the surface and construct an
> ordinary 2D square contour plot (with X1,X2 axes and X3 on the diagonal).
> However,  I would like to change the orientation of the plot so that the
> axes fit a parallelogram shaped grid made up from triangles. This would
> place X3 on the same scale as X1 and X2 and allow for an easier
> interpretation of the data for my research question.
>
> I hope this makes more sense! Thanks, Roary.
>
>
> Uwe Ligges-3 wrote
>> Not sure if I understand the question: If you have more data the grid
>> produced by image() or contour() will be finer anyway...
>> Perhaps we just need an example what you are actually asking for.
>>
>> Uwe Ligges
>>
>>
>> On 20.01.2012 13:28, Roary wrote:
>>> Hi All,
>>>
>>> I have 3 variables which present a perfect linear dependency such that
>>> the
>>> third is the sum of the first two. I have an ordinary 2D contour plot on
>>> a
>>> square grid with the first two variables forming the axes and the third
>>> naturally being the diagonals. From an interpretive point of view it
>>> would
>>> be nice to plot these two variables on a finer grid such that the third
>>> can
>>> have the same scaling (i.e. a finer grid) as the first two and this would
>>> look better on a triangular mesh. Is this possible in R?
>>>
>>> Many thanks,
>>>
>>> Roary
>>>
>>>