Dear R-helpers Can anyone direct me to a method for plotting what you might call a partial wireframe plot? I have two explanatory variables in a dataset which give me a significant interaction term when I fit a model. The two variables are correlated with each other to a moderate degree, and if I plot the predicted values from the model as a surface in a 3D wireframe plot there are some quite large parts of the surface that don't actually represent reasonable values for both variables. I'd like to only plot the parts of the surface that correspond to values of X and Y that are present in my dataset, which would give a surface with some corners missing. I can't see any way of specifying parts of the grid that should not be drawn: can anyone enlighten me? Alternatively, is it possible to shade specified squares of the plot to indicate the important parts of it? Thanks for any help Rob Knell School of Biological Sciences Queen Mary, University of London
Partial wireframe plots
2 messages · Rob Knell, Brian Ripley
On Mon, 10 Jan 2005, Rob Knell wrote:
Can anyone direct me to a method for plotting what you might call a partial wireframe plot? I have two explanatory variables in a dataset which give me a significant interaction term when I fit a model. The two variables are correlated with each other to a moderate degree, and if I plot the predicted values from the model as a surface in a 3D wireframe plot there are some quite large parts of the surface that don't actually represent reasonable values for both variables. I'd like to only plot the parts of the surface that correspond to values of X and Y that are present in my dataset, which would give a surface with some corners missing. I can't see any way of specifying parts of the grid that should not be drawn: can anyone enlighten me? Alternatively, is it possible to shade specified squares of the plot to indicate the important parts of it?
Note what ?persp says about NA values: I believe wireframe (lattice) does the same thing, that is only plot the grid over the region of finite (non-NA, non-Inf) values, at least provided it is a sensible shape.
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