leaflet-canvaslayer-field
Version:
A set of layers using canvas to draw ASCIIGrid or GeoTIFF files. This includes a basic raster layer (*ScalaField*) and an animated layer for vector fields, such as wind or currents (*VectorFieldAnim*)
102 lines (86 loc) • 4.06 kB
HTML
<html>
<head>
<title>VectorFieldAnim / ScalarField</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
<link rel="stylesheet" href="//unpkg.com/leaflet@1.2.0/dist/leaflet.css" />
<link rel="stylesheet" href="examples.css" />
<link href="https://fonts.googleapis.com/css?family=Roboto:100,400" rel="stylesheet">
</head>
<body>
<h1 class="title mapTitle">VectorFieldAnim > ScalarField</h1>
<div id="map"></div>
<!-- CDN -->
<script src="//d3js.org/d3.v4.min.js"></script>
<script src="//npmcdn.com/leaflet@1.2.0/dist/leaflet.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/chroma-js/1.3.0/chroma.min.js"></script>
<!-- Plugin -->
<script src="dist/leaflet.canvaslayer.field.js"></script>
<script>
let map = L.map("map");
// Basemap
let url = 'https://cartodb-basemaps-{s}.global.ssl.fastly.net/dark_nolabels/{z}/{x}/{y}.png';
L.tileLayer(url, {
attribution: 'OSM & Carto',
subdomains: 'abcd',
maxZoom: 19
}).addTo(map);
// ScalarField derived from a Vectorfield
d3.text('data/Atlantic_U.asc', function (u) {
d3.text('data/Atlantic_V.asc', function (v) {
const toMetersPerSecond = 0.001;
const vf = L.VectorField.fromASCIIGrids(u, v, toMetersPerSecond);
// a) First derived field: Magnitude (m/s)
const s = vf.getScalarField('magnitude'); // << derived ScalarField
/* custom scale, based on 'earth.nullschool.net'
(example: https://earth.nullschool.net/#current/ocean/surface/currents/overlay=currents/equirectangular=-11.95,29.62,1112)
*/
const magnitude = L.canvasLayer.scalarField(s, {
color: chroma.scale(
['#1F263A', '#414AA9', '#44758C', '#399B58', 'DCD296', 'F2E899', 'A53E3C', '9C3333'], [.1, .2, .3, .4, .7, .9, 1.5, 2]
),
opacity: 0.65
});
// b) Second derived field: DirectionFrom (º): (0 to 360º) | N is 0º and E is 90º
const direction = L.canvasLayer.scalarField(
vf.getScalarField('directionFrom'), {
type: 'vector',
color: 'white',
vectorSize: 25,
arrowDirection: 'from'
});
const animation = L.canvasLayer.vectorFieldAnim(vf, {
paths: 5000,
fade: 0.97,
maxAge: 100,
velocityScale: 1 / 40,
color: 'rgba(255, 255, 255, 0.7)'
}).addTo(map);
L.control.layers({}, {
"Vector animation": animation,
"Derived magnitude": magnitude,
"Derived direction": direction,
}, {
position: 'bottomleft',
collapsed: false
}).addTo(map);
map.fitBounds(animation.getBounds());
magnitude.on('click', function (e) {
if (e.value !== null) {
let v = e.value.toFixed(2);
let html = (`<span class="popupText">magnitude: ${v} m/s</span>`);
let popup = L.popup().setLatLng(e.latlng).setContent(html).openOn(map);
}
});
direction.on('click', function (e) {
if (e.value !== null) {
let v = e.value.toFixed(0);
let html = (`<span class="popupText">direction: ${v}º</span>`);
let popup = L.popup().setLatLng(e.latlng).setContent(html).openOn(map);
}
});
});
});
</script>
</body>
</html>