Leaflet Streamlines

Visualise two dimensional vector fields in leaflet using stream lines.

Grid of simulated water velocity values on Lake Geneva from the Meteolakes project, plotted as streamlines.

Check out the examples:

• Basic (source)

This project is inspired by earth and borrows code from the IH.Leaflet.CanvasLayer.Field project.

Quick start

import L from "leaflet";
import 'leaflet-streamlines';

or

<link
    rel="stylesheet"
    href="https://unpkg.com/leaflet@1.7.1/dist/leaflet.css"
    integrity="sha512-xodZBNTC5n17Xt2atTPuE1HxjVMSvLVW9ocqUKLsCC5CXdbqCmblAshOMAS6/keqq/sMZMZ19scR4PsZChSR7A=="
    crossorigin=""
/>
<script
    src="https://unpkg.com/leaflet@1.7.1/dist/leaflet.js"
    integrity="sha512-XQoYMqMTK8LvdxXYG3nZ448hOEQiglfqkJs1NOQV44cWnUrBc8PkAOcXy20w0vlaXaVUearIOBhiXZ5V3ynxwA=="
    crossorigin=""
></script>
<script type="text/javascript" src="https://unpkg.com/leaflet-streamlines"></script>

then

var map = L.map("map");
L.streamlines(data, options).addTo(map);

API reference

data

Data must be an object {u: [[]], v:[[]]} where u and v are 2D arrays of equivalent shape. u: y veloctiy (northward) v: x veloctiy (eastward)

options

Option	Description	Default	Type
xMax (Required)	Maximum x coordinate		Number
xMin (Required)	Minimum x coordinate		Number
yMax (Required)	Maximum y coordinate		Number
yMin (Required)	Minimum y coordinate		Number
paths	Number of streamlines to plot	800	Number
color	Color of streamlines, either a html color ("white", #FF5733) or a function that returns a color based on a single input of velocity magnitude.	white	Custom
width	Width of the streamline	0.5	Number
fade	Control the streamline fade	0.97	Number
duration	Milliseconds between timesteps	10	Number
maxAge	Max number of timesteps for streamline	50	Number
velocityScale	Factor to toggle speed of streamlines	0.01	Number
opacity	Opacity of streamlines	1	Number