leaflet-semicircle

Draw semicircles on Leaflet maps

Usage no npm install needed!

<script type="module">
  import leafletSemicircle from 'https://cdn.skypack.dev/leaflet-semicircle';
</script>

README

Leaflet-Semicircle.

Allows drawing semicircles on leaflet maps.

It's an extension of Leaflet's L.Circle, and behaves like L.Circle if the a semicircle of almost 360 degrees is displayed.

Updated for use with leaflet 1.1.0.

Provided classes:

Provided methods:

L.SemiCircle/ L.SemiCircleMarker
factories: L.semiCircle/L.SemiCircleMarker 		Options:
startAngle: start angle of the semicircle
stopAngle: stop angle of the semicircle
Angles are defined like compass courses: 0 = north, 90 = east, etc.
L.SemiCircle.setStartAngle(angle) Set the start angle of the circle to angle and redraw.
L.Circle.setStopAngle(angle) Set the stop angle of the circle to angle and redraw.
L.Circle.setDirection(direction, size) Set the startAngle to direction - (0.5 * size) and the stopAngle to direction + (0.5 * size) and redraw.

Usage:

The plugin provides two ways to only display a part of the circle:

  1. Use the options map and set startAngle and stopAngle.
  2. Use setDirection(direction, size) to display a semicircle of size degrees at direction.

Example:

Live demo

Using options.startAngle and options.stopAngle:

L.semiCircle([51.5, -0.09], {
    radius: 500,
    startAngle: 45,
    stopAngle: 135
}).addTo(map);

Draw the same semicircle using setDirection(direction, size):

L.semiCircle([51.5, -0.09], {radius: 500})
    .setDirection(90, 90)
    .addTo(map);

Screenshot:

Live demo

Semicircles screenshot

Changelog

2.0.2 (2017-09-01)

  • Fixed #24: instance check for canvas renderer

2.0.1 (2017-07-22)

  • Fixed #14: Poleward displacement of circle center when radius is large.

2.0.0 (2017-07-09)

  • Changed the API to stand-alone classes rather than overwriting L.Circle with an extension of itself.
  • Added support for Leaflet 1.1.0