misc3d: image3d – R documentation

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image3d

Draw Points on a 3D Grid

Description

Plots points on a three dimensional grid representing values in a three dimensional array. Assumes high values are inside and uses alpha blending to make outside points more transparent.

Usage

image3d(v, x = 1:dim(v)[1], y = 1:dim(v)[2], z = 1:dim(v)[3],
          vlim = quantile(v, c(.9, 1),na.rm=TRUE),
          col = heat.colors(256), alpha.power = 2,
          alpha = ((1:length(col))/ length(col))^alpha.power,
          breaks, sprites = TRUE, jitter = FALSE, 
          radius = min(diff(x), diff(y), diff(z)),
          add = FALSE,...)

Arguments

`v`	three dimensional data array.
`x,y,z`	locations of grid planes at which values in `v` are measured.
`vlim`	minimum and maximum `v` values for which points are to be drawn.
`col`	vector of colors for the points as generated by `heat.colors` or similar functions.
`alpha.power`	used to calculate the alpha values. The larger the power, the smaller the alpha, the more transparent the point. Only used if `alpha` is not supplied.
`alpha`	vector of alpha values between 0 and 1. The length of the vector should be equal to the length of `col`.
`breaks`	breakpoints for the colors; must give one more breakpoint than colors.
`sprites`	logical; if `TRUE`, use `sprites3d` to draw the points.
`radius`	radius used in `sprites3d`.
`jitter`	logical; if `TRUE`, add a small amount of noise to the point locations.
`add`	logical; if `TRUE`, add to current `rgl` graph.
`...`	material and texture properties. See `rgl.material` for details.

References

Daniel Adler, Oleg Nenadic and Walter Zucchini (2003) RGL: A R-library for 3D visualization with OpenGL

Examples

# view density of mixture of tri-variate normals
    nmix3 <- function(x, y, z, m, s) {
      0.4 * dnorm(x, m, s) * dnorm(y, m, s) * dnorm(z, m, s) +
        0.3 * dnorm(x, -m, s) * dnorm(y, -m, s) * dnorm(z, -m, s) +
          0.3 * dnorm(x, m, s) * dnorm(y, -1.5 * m, s) * dnorm(z, m, s)
    }
    f <- function(x,y,z) nmix3(x,y,z,.5,.5)
    x<-seq(-2,2,len=50)
    g <- expand.grid(x = x, y = x, z = x)
    v <- array(f(g$x, g$y, g$z), c(length(x), length(x), length(x)))
    image3d(v)
    image3d(v, jitter = TRUE)

misc3d

Miscellaneous 3D Plots

v0.9-0

GPL

Authors

Dai Feng and Luke Tierney

Initial release