Plot GAT Maps

This function draws a choropleth map of a numeric variable. It includes options to display summary statistics and subtitle. The legend produced is dependent on the dataset; if there are no exclusions, no areas below the minimum aggregation value, and no areas with missing rates, their respective entries will be excluded from the legend.

plotGATmaps(
  area,
  var,
  clr = "Blues",
  title.main = "",
  class = NULL,
  after = FALSE,
  title.sub = NULL,
  breaks = 5,
  colcode = NULL,
  mapstats = FALSE,
  ratemap = FALSE,
  closemap = FALSE
)

Arguments

area

A spatial polygons data frame.

var

A numeric variable within the spatial polygons data frame.

clr

The color scheme to use for the map, from RColorBrewer.

title.main

The map's main title as a text string.

class

The cut points for the choropleth categories. Default is NULL, in which case the function calculates breaks from the data using the breaks value.

after

Boolean denoting whether the function is mapping the aggregated area "after" map.

title.sub

The map's subtitle (if relevant) as a text string.

breaks

Number of categories for the choropleth.

colcode

Color code predefined for before/after maps.

mapstats

A boolean denoting whether or not to include summary statistics: min, median, and max.

ratemap

Boolean denoting whether the variable that is to be plotted contains decimal values that require rounding. In GAT, this applies to the GAT-calculated rate.

closemap

A boolean to denote whether to close the map window after the map is drawn and saved.

Details

The map produced by this function is designed to be saved to a recordPlot object for later rendering in a PDF rather than displayed directly. If plotting directly, the display may be distorted. For best results, save to a recordPlot object and write to PDF.

Examples

## plot population
# create a flag variable (used to check for and map exceptions)
hftown$GATflag <- 0

# plot the population
plotGATmaps(area = hfcw610k, var = "TOTAL_POP", clr = "YlGn",
  title.main = "Population", breaks = 3, mapstats = TRUE)

## to plot a rate
# create a randomized flag variable (data will not match labels here)
# 0 = no flag, 1-3 = excluded by user, 5 = above maximum aggregation value,
# 10 = below minimum aggregation value
hftown$GATflag <-
  sample(c(0, 1, 5, 10), nrow(hftown), replace = TRUE,
  prob = c(.8, .1, .05, .05))


# create a rate
hftown$pop_dens <- 10000 * hftown$TOTAL_POP / hftown$AREALAND
# add a couple random missings to illustrate uncalculated rates
hftown$pop_dens[sample(length(hftown), 2)] <- NA

# plot the rate
plotGATmaps(area = hftown, var = "pop_dens", clr = "YlGn",
  title.main = "population density", breaks = 3,
  mapstats = TRUE, ratemap = TRUE)