legends function

Legend Functions for Strucplots

These functions generate legend functions for residual-based shadings.

legend_resbased(fontsize = 12, fontfamily = "",
  x = unit(1, "lines"), y = unit(0.1,"npc"),
  height = unit(0.8, "npc"),
  width = unit(0.7, "lines"),
  digits = 2, pdigits = max(1, getOption("digits") - 2),
  check_overlap = TRUE, text = NULL,
  steps = 200, ticks = 10, pvalue = TRUE,  range = NULL)
legend_fixed(fontsize = 12, fontfamily = "", x = unit(1, "lines"), y = NULL,
  height = NULL, width = unit(1.5, "lines"), steps = 200,
  digits = 1, space = 0.05, text = NULL, range = NULL)

Arguments

• fontsize: fontsize of title and p-value text.
• fontfamily: fontfamily of all 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.
• pdigits: number of digits for the p-value.
• 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.
• range: Numeric vector of length 2 for setting the legend range. Computed from the residuals if omitted. NA values are replaced by the corresponding minimum / maximum of the residuals.

Returns

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.

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.

References

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. tools:::Rd_expr_doi("10.18637/jss.v017.i03") and available as vignette("strucplot").

Meyer, D., Zeileis, A., Hornik, K. (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. https://www.R-project.org/conferences/DSC-2003/Proceedings/

Author(s)

David Meyer David.Meyer@R-project.org

See Also

structable, shadings

Examples

data("Titanic")

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