Biostatistics with R

3D scatter plots

A three dimensional scatter plot shows points P(x,y,z) in three dimensiona space. The scatter3D() function of the plot3D graphics library in R creates nice three dimensional scatter plots.

The properties of the 3D scatter plot can be altered using some of the arguments to scatter3D() :

x,y,z ------> vectors with values along three axes theta, phi -----> the azimuthal and colattitude directions for viewing. Angles in degrees. box -----> To draw a box with axes. A value of TRUE draws a box. Default is TRUE. bty -----> Type of box to be drawn. Wroks when BOX=TRUE. Three types of
boxes for 3 options bty = "g", "b2","bl" axes -----> Boolean value of TRUE draws the axes. label -----> A value of TRUE enables the label for axes. nticks -----> An integer specifying the number of ticks on the 3 axes. For other parameters of this function, type help(scatter3D) in R prompt.
library(plot3D) # number of data points. npoints = 20 # generate sequences for X,Y values x = runif(npoints,1,20) y = runif(npoints,1,20) # generate random numbers between (0,30) for Z values z = 30*runif(npoints) # Call to scatter3D function scatter3D(x,y,z,box=TRUE,pch=16,bty="b2",axes=TRUE,label=TRUE, nticks=5, ticktype="detailed",theta=40, phi=40, xlab="X-val", ylab="Y-val", zlab="Z-val", main="3D scatter plot")

The resulting scatter plot is shown below: