legends {vcd} | R Documentation

## Legend Functions for Strucplots

### Description

These functions generate legend functions for residual-based shadings.

### Usage

    legend_resbased(fontsize = 12,
      x = unit(1, "lines"), y = unit(0.1,"npc"),
      height = unit(0.8, "npc"),
      width = unit(0.7, "lines"),
      digits = 3, check_overlap = TRUE, text = NULL,
      steps = 200, ticks = 10, pvalue = TRUE)
    legend_fixed(fontsize = 12, x = unit(1, "lines"), y = NULL,
      height = NULL, width = unit(1.5, "lines"), steps = 200,
      digits = 1, space = 0.05, text = NULL)

### Arguments

`fontsize` | fontsize of title and p-value text.
`x, y` | objects of class `"unit"` indicating the coordinates of the title. For `legend_fixed`, the default for `y` is computed as to leave enough space for the specified `text`.
`height, width` | object of class `"unit"` indicating the height/width of the legend. For `legend_fixed`, the default for `y` is computed as to align upper margins of legend and actual plot.
`digits` | number of digits for the scale labels.
`check_overlap` | logical indicating whether overlap of scale labels should be inhibited or not.
`space` | For `legend_fixed` only: proportion of space between the tiles.
`text` | character string indicating the title of the legend.
`steps` | granularity of the color gradient.
`ticks` | number of scale ticks.
`pvalue` | logical indicating whether the p-value should be visualized under the scale or not.

### Details

These functions generate legend functions for residual-based shadings, visualizing deviations from expected values of an hypothesized independence model. Therefore, the legend uses a supplied shading function to visualize the color gradient for the residuals range. `legend_fixed` is inspired by the legend used in `mosaicplot`. For more details on the shading functions and their return values, see `shadings`.

### Value

A function with arguments:

`residuals` | residuals from the fitted independence model to be visualized.
`shading` | shading function computing colors from residuals (see details).
`autotext` | character vector indicating the title to be used when no `text` argument is specified. Allows strucplot to generate sensible defaults depending on the residuals type.

### Author(s)

David Meyer David.Meyer@R-project.org

### References

D. Meyer, A. Zeileis, K. Hornik (2003), Visualizing independence using extended association plots. Proceedings of the 3rd International Workshop on Distributed Statistical Computing, K. Hornik, F. Leisch, A. Zeileis (eds.), ISSN 1609-395X. http://www.ci.tuwien.ac.at/Conferences/DSC-2003/Proceedings/

### See Also

`structable`, `shadings`

### Examples

    mosaic(Titanic, shade = TRUE, legend = legend_resbased)
    mosaic(Titanic, shade = TRUE, legend = legend_fixed, gp = shading_Friendly)

[Package vcd version 0.9-6 Index]