Public
Edited
Nov 15, 2023
1 star
usStates = FileAttachment("us-states.json").json()
{
const container = yield htl.html`<div style="height: 500px;">`;
const map = L.map(container).setView([37.8, -96], 4);
const geojson = L.geoJson(usStates, {
style: style,
onEachFeature: onEachFeature
}).addTo(map);
L.tileLayer("https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png", {
maxZoom: 19,
attribution: "© <a href=https://www.openstreetmap.org/copyright>OpenStreetMap</a> contributors"
}).addTo(map);
// Adding interaction
function highlightFeature(e) {
var layer = e.target;
layer.setStyle({
weight: 2,
color: '#666',
dashArray: '',
fillOpacity: 0.6
});
layer.bringToFront();
info.update(layer.feature.properties);
}
function resetHighlight(e) {
geojson.resetStyle(e.target);
info.update();
}
function zoomToFeature(e) {
map.fitBounds(e.target.getBounds());
}
function onEachFeature(feature, layer) {
layer.on({
mouseover: highlightFeature,
mouseout: resetHighlight,
click: zoomToFeature
});
}
// Custom info control
const info = L.control();
info.onAdd = function (map) {
this._div = L.DomUtil.create('div', 'info'); // create a div with a class "info"
this.update();
return this._div;
};
// method that we will use to update the control based on feature properties passed
info.update = function (props) {
this._div.innerHTML = '<h4>US Population Density</h4>' + (props ?
'<b>' + props.name + '</b><br />' + props.density + ' people / mi<sup>2</sup>'
: 'Hover over a state');
};
info.addTo(map);
// Custom legend
var legend = L.control({position: 'bottomright'});
legend.onAdd = function (map) {
var div = L.DomUtil.create('div', 'info legend'),
grades = [0, 10, 20, 50, 100, 200, 500, 1000],
labels = [];
// loop through our density intervals and generate a label with a colored square for each interval
for (var i = 0; i < grades.length; i++) {
div.innerHTML +=
'<i style="background:' + getColor(grades[i] + 1) + '"></i> ' +
grades[i] + (grades[i + 1] ? '–' + grades[i + 1] + '<br>' : '+');
}
return div;
};
legend.addTo(map);
}
html`
<style type="text/css">
.info {
padding: 6px 8px;
font: 14px/16px Arial, Helvetica, sans-serif;
background: white;
background: rgba(255,255,255,0.8);
box-shadow: 0 0 15px rgba(0,0,0,0.2);
border-radius: 5px;
}
.info h4 {
margin: 0 0 5px;
color: #777;
}
.legend {
line-height: 18px;
color: #555;
}
.legend i {
width: 18px;
height: 18px;
float: left;
margin-right: 8px;
opacity: 0.7;
}
`
function getColor(d) {
return d > 1000 ? '#800026' :
d > 500 ? '#BD0026' :
d > 200 ? '#E31A1C' :
d > 100 ? '#FC4E2A' :
d > 50 ? '#FD8D3C' :
d > 20 ? '#FEB24C' :
d > 10 ? '#FED976' :
'#FFEDA0';
}
function style(feature) {
return {
fillColor: getColor(feature.properties.density),
weight: 1,
opacity: 1,
color: 'white',
dashArray: '2',
fillOpacity: 0.7
};
}
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
