A ggplot2 geometry to plot event steps as paths

This function provides a ggplot2 geometry to plot steps between events as paths. It uses move2::mt_segments() to create sf lines joining each consecutive pair of events (i.e. steps. These steps are then added to the events table (with a point for the last event of each track), so that all variables in the event table are available for mapping the aesthetics. The resulting sf lines are then plotted via a wrapper around [ggplot2::geom_sf()], thus allowing for projections to be set using the ggplot2::coord_sf()` function. See ggplot2::geom_sf() for details.

Usage

geom_event_path(
  mapping = ggplot2::aes(),
  data = NULL,
  drop_final_point = TRUE,
  stat = "sf",
  position = "identity",
  na.rm = FALSE,
  show.legend = NA,
  ...
)

Arguments

mapping

Set of aesthetic mappings created by ggplot2::aes(). Variables from the events table can be used for mapping. If none is provided a basic aesthetics for the sf step segments (i.e. lines) will be used, as it is the case for ggplot2::geom_sf().

data

The move2 object to be displayed. For this geometry, there is no inheritance from the main ggplot() call, and data has to be specified.

drop_final_point

Logical, default is TRUE. The move2::mt_segments function cannot create a segment for the final point in each track, so it is left as a POINT geometry. If TRUE, we filter to LINESTRING geometries only (this is necessary for the animation function to work).

stat

The statistical transformation to use on the data for this layer. The default is "sf", which should normally be left unchanged.

position

The position adjustment to use for overlapping points on this layer. The default is "identity", meaning no adjustment will be made to the data.

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

show.legend

logical. Should this layer be included in the legends? The default is NA, which includes if any aesthetics are mapped. It can also be a named logical vector to finely select the aesthetics to display.

...

Other arguments passed on to ggplot2::layer().

Value

A ggplot2 layer object.

Details

Units (implemented via the package units) are produced by many operations, but are not fully compatible with ggplot2. This function internally drops units before creating a ggplot2 layer.

Examples

library(ggplot2)
ggplot() +
  geom_event_path(data = example_tt, mapping = aes(color = track_id))