https://github.com/jolars/polylabelr

Find the Pole of Inaccessibility (Visual Center) of a Polygon
https://github.com/jolars/polylabelr

Last synced: 2 days ago
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Find the Pole of Inaccessibility (Visual Center) of a Polygon

• Host: GitHub
• URL: https://github.com/jolars/polylabelr
• Owner: jolars
• License: other
• Created: 2018-10-23T06:36:46.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2021-01-27T18:39:55.000Z (almost 4 years ago)
• Last Synced: 2024-10-26T23:12:21.783Z (16 days ago)
• Language: C++
• Homepage: https://jolars.github.io/polylabelr/
• Size: 144 KB
• Stars: 17
• Watchers: 3
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.Rmd
  • License: LICENSE

Awesome Lists containing this project

README

        
---

output: github_document

---

```{r setup, include = FALSE}

knitr::opts_chunk$set(

  collapse = TRUE,

  comment = "#>",

  fig.path = "man/figures/README-",

  out.width = "100%"

)

```

# polylabelr

[![R build status](https://github.com/jolars/polylabelr/workflows/R-CMD-check/badge.svg)](https://github.com/jolars/polylabelr/actions)

[![Travis build status](https://travis-ci.com/jolars/polylabelr.svg?branch=master)](https://travis-ci.com/jolars/polylabelr)

[![AppVeyor build status](https://ci.appveyor.com/api/projects/status/github/jolars/polylabelr?branch=master&svg=true)](https://ci.appveyor.com/project/jolars/polylabelr)

[![Coverage status](https://codecov.io/gh/jolars/polylabelr/branch/master/graph/badge.svg)](https://codecov.io/github/jolars/polylabelr?branch=master)

[![CRAN status](https://www.r-pkg.org/badges/version/polylabelr)](https://cran.r-project.org/package=polylabelr)

**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/).