---
title: "Radial space-use profile of a grid-based home range"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Radial space-use profile of a grid-based home range}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)
```

```{r setup}
library(gridHR)
```

`radial_plot()` summarizes how space-use intensity changes with distance from
the centre toward the periphery of a grid-based home range. The function
divides the occupied grid cells into radial rings and calculates the
space-use intensity of each ring as the number of recorded locations divided
by the number of occupied cells in that ring.

This produces a radial space-use profile: a representation of the relationship
between distance from the centre of the home range and the relative intensity
with which space is used. Distance and intensity are normalized from 0 to 1,
allowing profiles to be compared independently of the absolute size of the
home range or the number of locations.

The centre is defined from the geometric centroid of the observed locations,
using the centre of the grid cell containing that centroid. Distance is then
measured from this central cell to the centres of the occupied cells.

```{r}
radial_plot(
  gibbons,
  cell_area = 5000,
  cell_shape = "hex",
  title = "Radial space-use profile of a gibbon group (0.5-ha hexagons)"
)
```