scatter3dHH: Three-Dimensional Scatterplots and Point Identification

Description

The scatter3d function uses the rgl package to draw 3D scatterplots with various regression surfaces. The function Identify3d allows you to label points interactively with the mouse: Press the right mouse button (on a two-button mouse) or the centre button (on a three-button mouse), drag a rectangle around the points to be identified, and release the button. Repeat this procedure for each point or set of ``nearby'' points to be identified. To exit from point-identification mode, click the right (or centre) button an empty region of the plot.

This is a revision of the Rcmdr scatter3d to add the ability to plot squared residuals.

Usage

scatter3dHH(x, y, z,
    xlab=deparse(substitute(x)), ylab=deparse(substitute(y)),
    zlab=deparse(substitute(z)),
    revolutions=0, bg.col=c("white", "black"),
    axis.col=if (bg.col == "white") "black" else "white",
    surface.col=c("blue", "green", "orange", "magenta",
        "cyan", "red", "yellow", "gray"),
    neg.res.col="red", pos.res.col="green", point.col="yellow",
    text.col=axis.col,
    grid.col=if (bg.col == "white") "black" else "gray",
    fogtype=c("exp2", "linear", "exp", "none"),
    residuals=(length(fit) == 1), surface=TRUE, grid=TRUE,
    grid.lines=26, df.smooth=NULL, df.additive=NULL,
    sphere.size=1, threshold=0.01, speed=1, fov=60,
    fit="linear", groups=NULL, parallel=TRUE, model.summary=FALSE,
    squares = FALSE, square.color = "gray", coef.ratio = 1, ...)

Value

scatter3d not return a useful value; it is used for its side-effect of creating a 3D scatterplot. Identify3d returns the labels of the identified points.

Arguments

x: variable for horizontal axis.
y: variable for vertical axis (response).
z: variable for out-of-screen axis.
xlab, ylab, zlab: axis labels.
revolutions: number of full revolutions of the display.
bg.col: background colour; one of "white", "black".
axis.col: colour for axes; default is "white" for black background, "black" for white background.
surface.col: vector of colours for regression planes, used in the order specified by fit.
neg.res.col, pos.res.col: colours for lines representing negative and positive residuals.
point.col: colour of points.
text.col: colour of axis labels.
grid.col: colour of grid lines on the regression surface(s).
fogtype: type of fog effect; one of "exp2", "linear", "exp", "none".
residuals: plot residuals (TRUE or FALSE); available only when there is one surface plotted.
surface: plot surface(s) (TRUE or FALSE).
grid: plot grid lines on the regression surface(s) (TRUE or FALSE).
grid.lines: number of lines (default, 26) forming the grid, in each of the x and y directions.
df.smooth: degrees of freedom for the two-dimensional smooth regression surface; if NULL (the default), the gam function will select the degrees of freedom for a smoothing spline by generalized cross-validation; if a positive number, a fixed regression spline will be fit with the specified degrees of freedom.
df.additive: degrees of freedom for each explanatory variable in an additive regression; if NULL (the default), the gam function will select degrees of freedom for the smoothing splines by generalized cross-validation; if a positive number or a vector of two positive numbers, fixed regression splines will be fit with the specified degrees of freedom for each term.
sphere.size: relative sizes of spheres representing points; the actual size is dependent on the number of observations.
threshold: if the actual size of the spheres is less than the threshold, points are plotted instead.
speed: relative speed of revolution of the plot.
fov: field of view (in degrees); controls degree of perspective.
fit: one or more of "linear", "quadratic", "smooth", "additive"; to display fitted surface(s); partial matching is supported -- e.g., c("lin", "quad").
groups: if NULL (the default), no groups are defined; if a factor, a different surface or set of surfaces is plotted for each level of the factor; in this event, the colours in plane.col are used successively for the points, surfaces, and residuals corresponding to each level of the factor.
parallel: when plotting surfaces by groups, should the surfaces be constrained to be parallel? A logical value, with default TRUE.
model.summary: print summary or summaries of the model(s) fit (TRUE or FALSE).
col: colours for the point labels, given by group. There must be at least as many colours as groups; if there are no groups, the first colour is used. Normally, the colours would correspond to the plane.col argument to scatter3d.
squares: logical. If TRUE, the residuals are plotted as squares. The sum of the area of the squares is the "residual sum of squares". If FALSE, the residuals are plotted as vertical lines.
square.color: color for the squares.
coef.ratio: number, defaults to 1. Settig coef.ratio to a number other than 1 is a primitive way of plotting squared pseudo-residuals that are not the least-squares residuals. The reason for displaying non-least-squares residuals is to compare them to the least-squares residuals and thus get a 3d visual image of what minimizing the sum of squares actually means.
...: other arguments are ignored.

Author

John Fox jfox@mcmaster.ca. Squared residuals added by Richard M. Heiberger <rmh@temple.edu>.

Examples

Run this code

    if (FALSE) {
State.x77 <- as.data.frame(state.x77)
with(State.x77, scatter3d(Income, Murder, Illiteracy))
with(State.x77, Identify3d(Income, Murder, Illiteracy, labels=row.names(State.x77)))
with(State.x77,  scatter3d(Income, Murder, Illiteracy, fit=c("linear", "quadratic")))
    }