webmapping_demos/leaflet_practice.html at master · HenshawW-io/webmapping_demos · GitHub

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<!DOCTYPE html>
<html>
    <head>
        <style>
            html, body {
                height: 500px;
                padding: 0;
                margin: 0;
            }
            #map {
                height: 500px;
                width: 100%;
                overflow: hidden;
                float: left;
                border: thin solid #333;
            }

            .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;
            }

        </style>
        <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 src='javascript/us-states.js'></script>
    </head>
    <body>
        <div id="mapid" style="width: 100%; height: 400px;"></div>

        <script>
            var map = L.map('mapid').setView([37.090240, -95.712891], 0);
            L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
                attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
            }).addTo(map);

            var colors = ['#edf8fb', '#bfd3e6', '#9ebcda', '#8c96c6', '#8c6bb1', '#88419d', '#6e016b']
            function getColor(d) {
                return d > 1000 ? colors[0]:
                d > 500 ? colors[1]:
                d > 200 ? colors[2]:
                d > 100 ? colors[3]:
                d > 50 ? colors[4]:
                d > 20 ? colors[5]:
                d > 10 ? colors[6]:
                        '#A5B4EC';
            }

            function style(feature) {
                return {
                    fillColor: getColor(feature.properties.density),
                    weight: 2,
                    opacity: 1,
                    color: 'white',
                    dashArray: '3',
                    fillOpacity: 0.7
                };
            }
            // same technique, but with if ... else
            // function getColor(d) {
            //     if (d > 1000) { return colors[0] }
            //     else if (d > 500) { return colors[1] }
            //     else if (d > 200) { return colors[2] }
            //     else if (d > 100) { return colors[3] }
            //     else if (d > 50) { return colors[4] }
            //     else if (d > 20) { return colors[5] }
            //     else if (d > 10) { return colors[6] }
            //     else { return '#000000' }
            // }
            var geojson = L.geoJson(statesData, {style: style}).addTo(map);

            // If I want my map to appear on the extent of the GeoJson's
            map.fitBounds(geojson.getBounds());

            function highlightFeature(e) {
                var layer = e.target;
                layer.setStyle({
                    weight: 5,
                    color: '#666',
                    dashArray: '',
                    fillOpacity: 0.7
                });
                if (!L.Browser.ie && !L.Browser.opera && !L.Browser.edge) {
                    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
                });
            }
            geojson = L.geoJson(statesData, {
                style: style,
                onEachFeature: onEachFeature
            }).addTo(map);

            var info = L.control();

            info.onAdd = function (map) {
                this._div = L.DomUtil.create('div', 'info');
                this.update();
                return this._div;
            };

            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);

            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] ? '&ndash;' + grades[i + 1] + '<br>' : '+');
                }

                return div;
            };

            legend.addTo(map);
        </script>
    </body>
</html>