R: Core-generating Function for Association Plots

struc_assoc {vcd} | R Documentation

## Core-generating Function for Association Plots

### Description

Core-generating function for `strucplot` returning a function producing association plots.

### Usage

    struc_assoc(compress = TRUE, xlim = NULL, ylim = NULL,
      yspace = unit(0.5, "lines"), xscale = 0.9, gp_axis = gpar(lty = 3))

### Arguments

`compress` | logical; if `FALSE`, the space between the rows (columns) are chosen such that the total heights (widths) of the rows (column) are all equal. If `TRUE`, the space between the rows and columns is fixed and hence the plot is more “compressed”.
`xlim` | either a 2 x k matrix of doubles, k the number of total columns of the plot, or a recycled vector from which such a matrix will be constructed. The columns of `xlim` correspond to the columns of the association plot, the rows describe the column ranges (minimums in the first row, maximums in the second row). If `xlim` is `NULL`, the ranges are determined from the residuals according to `compress` (if `TRUE`: widest range from each column, if `FALSE`: from the whole association plot matrix).
`ylim` | either a 2 x k matrix of doubles, k the number of total rows of the plot, or a recycled vector from which such a matrix will be constructed. The columns of `ylim` correspond to the rows of the association plot, the rows describe the column ranges (minimums in the first row, maximums in the second row). If `ylim` is `NULL`, the ranges are determined from the residuals according to `compress` (if `TRUE`: widest range from each row, if `FALSE`: from the whole association plot matrix).
`xscale` | scale factor resizing the tile's width, thus adding additional space between the tiles.
`yspace` | object of class `"unit"` specifying additional space separating the rows.
`gp_axis` | object of class `"gpar"` specifying the visual aspects of the tiles' baseline.

### Details

This function is usually called by `strucplot` (typically when called by `assoc`) and returns a function used by `strucplot` to produce association plots.

### Value

A function with arguments:

`residuals` | table of residuals.
`observed` | not used by `struc_assoc`.
`expected` | table of expected frequencies.
`spacing` | object of class `"unit"` specifying the space between the tiles.
`gp` | list of `gpar` objects used for the drawing the tiles.
`split_vertical` | vector of logicals indicating, for each dimension of the table, the split direction.

### Author(s)

David Meyer David.Meyer@R-project.org

### References

Cohen, A. (1980), On the graphical display of the significant components in a two-way contingency table. Communications in Statistics—Theory and Methods, A9, 1025–1041.

Friendly, M. (1992), Graphical methods for categorical data. SAS User Group International Conference Proceedings, 17, 190–200. http://datavis.ca/papers/sugi/sugi17.pdf

Meyer, D., Zeileis, A., and Hornik, K. (2006), The strucplot framework: Visualizing multi-way contingency tables with vcd. Journal of Statistical Software, 17(3), 1-48. URL http://www.jstatsoft.org/v17/i03/ and available as `vignette("strucplot")`.

### See Also

`assoc`, `strucplot`, `structable`

### Examples

    ## UCB Admissions
    data("UCBAdmissions")
    ucb <- aperm(UCBAdmissions)

    ## association plot for conditional independence
    strucplot(ucb, expected = ~ Dept * (Admit + Gender),
      core = struc_assoc(ylim = c(-4, 4)), labeling_args = list(abbreviate = c(Admit = 3)))

[Package vcd version 1.4-4 Index]