Plot travel time matrix diagnostics

Visualize the distribution and spatial structure of travel times between census tracts and polling stations.

Usage

plot_travel_times(
  result,
  type = c("histogram", "heatmap", "map"),
  tract = NULL,
  ...
)

Arguments

result

An interpElections_result object.

type

Character. Plot type: "histogram", "heatmap", or "map". Default: "histogram".

tract

Tract ID or index for type = "map". NULL picks a random tract.

...

Ignored.

Value

A ggplot object (invisibly). Prints the plot.

Details

• "histogram": Distribution of all travel time values. Annotates the maximum value (potential fill value for unreachable pairs).

• "heatmap": Travel time matrix as a tile plot, with tracts ordered by latitude of their centroid. Reveals spatial locality.

• "map": For a selected tract, overlays station points colored by travel time from that tract.