leaflet-measure-path-xiaoai

Leaflet Measure Path

A plugin to show measurements on paths (polylines, polygons and circles currently supported).

Leaflet Measure Path demo

Installation

NPM

npm install @xiaoai/leaflet-measure-path

TypeScript

This package includes TypeScript definitions. For TypeScript projects:

import 'leaflet';
import '@xiaoai/leaflet-measure-path';

// Now you can use the measurement methods with full type support
const polygon = L.polygon([...])
    .addTo(map)
    .showMeasurements({
        showOnHover: true,
        showArea: true
    });

Usage

Load leaflet-measure-path.js and leaflet-measure-path.css. Then, to enable measurements on a path:

var polygon = L.polygon([ ... ])
    .addTo(map)
    .showMeasurements();

To later hide measurements:

var polygon = L.polygon([ ... ])
    .addTo(map)
    .hideMeasurements();

API

The simplest way to enable measurements for a path is to pass the option showMeasurements: true when creating the path. To control the measurement options, you can also pass measurementOptions, see options below.

The plugin also adds the methods listed below to Leaflet's L.Polyline, L.Polygon and L.Circle classes.

showMeasurements(options)

Enables measurements. You can also overide the defaults by passing an options object.

Options

• showOnHover: Boolean (default false): if true, the measurements will only show when the user hovers the cursor over the path
• showTotalDistance: Boolean (default true): if false, the total length of polyline will not be shown
• minDistance: Number (default 30): the minimum length a line segment in the feature must have for a measurement to be added
• formatDistance: Function: allows to override the built-in function that formats a distance in meters to the string shown in the map
• formatArea: Function: allows to override the built-in function that formats an area in square meters to the string shown in the map

hideMeasurements()

Disables measurements.

updateMeasurements()

Updates the measurements displayed. Normally, this method is called automatically if the path's geometry is changed using setLatLngs, spliceLatLngs or when the map is zoomed. If the geometry is somehow changed by other means, this method can be called to force the measurements to update.