Create an interpolation expression with automatic palette and break calculation

This function creates an interpolation expression by automatically calculating break points using different methods and applying a color palette. It handles the values/stops matching automatically and supports the same classification methods as the step functions.

Usage

interpolate_palette(
  column,
  data_values,
  method = "equal",
  n = 5,
  palette = viridisLite::viridis,
  na_color = "grey"
)

Arguments

column

The name of the column to use for the interpolation.

data_values

A numeric vector of the actual data values used to calculate breaks.

method

The method for calculating breaks. Options are "equal" (equal intervals), "quantile" (quantile breaks), or "jenks" (Jenks natural breaks). Defaults to "equal".

n

The number of break points to create. Defaults to 5.

palette

A function that takes n and returns a character vector of colors. Defaults to viridisLite::viridis.

na_color

The color to use for missing values. Defaults to "grey".

Value

A list of class "mapgl_continuous_scale" containing the interpolation expression and metadata.

Examples

if (FALSE) { # \dontrun{
# Create continuous color scale
data_values <- c(10, 25, 30, 45, 60, 75, 90)
scale <- interpolate_palette("value", data_values, method = "equal", n = 5)

# Use in a layer
add_fill_layer(map, fill_color = scale$expression)

# Extract legend information  
labels <- get_legend_labels(scale, format = "currency")
colors <- scale$colors
} # }