bi_legend {biscale}

Create Object for Drawing Legend

Description

Creates a ggplot object containing a legend that is specific to bivariate mapping.

Usage

bi_legend(pal, dim = 3, xlab, ylab, size = 10, flip_axes = FALSE,
    rotate_pal = FALSE, pad_width = NA, pad_color = "#ffffff",
    breaks = NULL, arrows = TRUE)

Arguments

pal

A palette name or a vector containing a custom palette. See the help file for bi_pal for complete list of built-in palette names. If you are providing a custom palette, it must follow the formatting described in the 'Advanced Options' vignette.

dim

The dimensions of the palette. To use the built-in palettes, this value must be either 2, 3, or 4. A value of 3, for example, would be used to create a three-by-three bivariate map with a total of 9 classes.

If you are using a custom palette, this value may be larger (though these maps can be very hard to interpret). See the 'Advanced Options' vignette for details on the relationship between dim values and palette size.

xlab

Text for desired x axis label on legend

ylab

Text for desired y axis label on legend

size

A numeric scalar; size of axis labels

flip_axes

A logical scalar; if TRUE, the axes of the palette will be flipped. If FALSE (default), the palette will be displayed on its original axes. Custom palettes with 'dim' greater than 4 cannot take advantage of flipping axes.

rotate_pal

A logical scalar; if TRUE, the palette will be rotated 180 degrees. If FALSE (default), the palette will be displayed in its original orientation. Custom palettes with 'dim' greater than 4 cannot take advantage of palette rotation.

pad_width

An optional numeric scalar; controls the width of padding between tiles in the legend

pad_color

An optional character scalar; controls the color of padding between tiles in the legend

breaks

An optional list created by bi_class_breaks. Depending on the options selected when making the list, labels will placed showing the corresponding range of values for each axis or, if split = TRUE, showing the individual breaks.

arrows

A logical scalar; if TRUE (default), directional arrows will be added to both the x and y axes of the legend. If you want to suppress these arrows, especially if you are supplying breaks to create a more detailed legend, this parameter can be set of FALSE.

Value

A ggplot object with a bivariate legend.

See Also

bi_pal

Examples

# sample 3x3 legend
legend <- bi_legend(pal = "GrPink",
                    dim = 3,
                    xlab = "Higher % White ",
                    ylab = "Higher Income ",
                    size = 16)

# print legend
legend

# sample 3x3 legend with breaks
## create vector of breaks
break_vals <- bi_class_breaks(stl_race_income, style = "quantile",
    x = pctWhite, y = medInc, dim = 3, dig_lab = c(x = 4, y = 5),
    split = TRUE)

## create legend
legend <- bi_legend(pal = "GrPink",
                    dim = 3,
                    xlab = "Higher % White ",
                    ylab = "Higher Income ",
                    size = 16,
                    breaks = break_vals,
                    arrows = FALSE)

# print legend
legend