xyzmat.coords {squash}

Extract (x, y, z) coordinates, where z is a matrix

Description

Extract (x, y, z) plotting coordinates, where z is a matrix.

Usage

xyzmat.coords(x = NULL, y = NULL, z = NULL, 
    xlab = NULL, ylab = NULL, zlab = NULL,
    xds = NULL, yds = NULL, zds = NULL)

Arguments

x, y

Numeric vectors.

z

A matrix

xlab, ylab, zlab

Labels

xds, yds, zds

Results from deparse(substitute(x)) (etc.); see below.

Details

This function is similar to xyz.coords, except that this function accepts a matrix for z.

If x is the same length as nrow(z), x will be taken as the points at which the z values were sampled. If x is the length of nrow(z) + 1, x is taken as the breakpoints between bins. If x is missing, the matrix indices (1:nrow(z)) will be used. Similarly for y and the columns of z.

For convenience, the matrix can supplied as the x argument. Or, x can be a list with elements including {x, y, z, xlab, ylab, zlab}.

When this function is used inside a higher-level plotting function, the arguments xds, yds, and zds should be set to deparse(substitute(x)) (etc.) so that the function can generate informative default axis labels. For example, see the code for colorgram.

Value

A list with the following components:

x

X coordinates

y

Y coordinates

z

Z matrix

xlab

Label for X axis

ylab

Label for Y axis

zlab

Label for Z axis

Examples

  ## 
  str(volcano)
  volcano.xyzmat <- xyzmat.coords(volcano)
  str(volcano.xyzmat)