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README.Rmd
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README.Rmd
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---
output: github_document
---
<!-- README.md is generated from README.Rmd. Please edit that file -->
```{r setup, include = FALSE}
knitr::opts_chunk$set(
collapse = TRUE,
comment = "#>",
fig.path = "man/figures/README-",
out.width = "100%"
)
```
# polylabelr
<!-- badges: start -->
[](https://github.com/jolars/polylabelr/actions)
[](https://travis-ci.com/jolars/polylabelr)
[](https://ci.appveyor.com/project/jolars/polylabelr)
[](https://codecov.io/github/jolars/polylabelr?branch=master)
[](https://cran.r-project.org/package=polylabelr)
<!-- badges: end -->
**polylabelr** is an R wrapper for the
[polylabel package](https://github.com/mapbox/polylabel)
from [Mapbox](https://www.mapbox.com/). It currently contains a single function,
`poi()` that finds the *pole of inaccessibility* of a polygon, which usually
makes for a good place to put a label on a polygon---hence the name.
## Usage
```{r}
# a concave polygon
x <- c(0, 4, 1, 6, 7, 7, 0, 0)
y <- c(0, 0, 1, 2, 1, 3, 2, 0)
# locate the pole of inaccessibility
p <- polylabelr::poi(x, y, precision = 0.01)
plot.new()
plot.window(range(x, na.rm = TRUE), range(y, na.rm = TRUE))
polypath(x, y, col = "grey", border = FALSE)
points(p)
```
## Installation
### CRAN version
```{r, eval = FALSE}
install.packages("polylabelr")
```
### Development version
```{r, eval = FALSE}
remotes::install_github("jolars/polylabelr")
```
## Modifications
The source code from [polylabel](https://github.com/mapbox/polylabel)
and [geometry.hpp](https://github.com/mapbox/geometry.hpp/) has been
modified in a few ways to compile properly with c++11 using the
standard flags required by CRAN policies. polylabel has also
been modified to return the distance from the chosen point to the
enclosing polygon, in case it is of value to users.
## Versioning
**polylabelr** uses [semantic versioning](https://semver.org/).