ズーム・レベルでコロプレスレイヤーを更新

2014 年の国勢調査データを使用して、ズームレベルに従い州または郡の人口を表示します。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>ズーム・レベルでコロプレスレイヤーを更新</title>
<meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />
<script src="https://api.mapbox.com/mapbox-gl-js/v1.6.1/mapbox-gl.js"></script>
<link href="https://api.mapbox.com/mapbox-gl-js/v1.6.1/mapbox-gl.css" rel="stylesheet" />
<style>
	body { margin: 0; padding: 0; }
	#map { position: absolute; top: 0; bottom: 0; width: 100%; }
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<body>
<style>
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background-color: #fff;
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bottom: 30px;
box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
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right: 10px;
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.legend h4 {
margin: 0 0 10px;
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.legend div span {
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height: 10px;
margin-right: 5px;
width: 10px;
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</style>
 
<div id="map"></div>
 
<div id="state-legend" class="legend">
<h4>Population</h4>
<div><span style="background-color: #723122"></span>25,000,000</div>
<div><span style="background-color: #8B4225"></span>10,000,000</div>
<div><span style="background-color: #A25626"></span>7,500,000</div>
<div><span style="background-color: #B86B25"></span>5,000,000</div>
<div><span style="background-color: #CA8323"></span>2,500,000</div>
<div><span style="background-color: #DA9C20"></span>1,000,000</div>
<div><span style="background-color: #E6B71E"></span>750,000</div>
<div><span style="background-color: #EED322"></span>500,000</div>
<div><span style="background-color: #F2F12D"></span>0</div>
</div>
 
<div id="county-legend" class="legend" style="display: none;">
<h4>Population</h4>
<div><span style="background-color: #723122"></span>1,000,000</div>
<div><span style="background-color: #8B4225"></span>500,000</div>
<div><span style="background-color: #A25626"></span>100,000</div>
<div><span style="background-color: #B86B25"></span>50,000</div>
<div><span style="background-color: #CA8323"></span>10,000</div>
<div><span style="background-color: #DA9C20"></span>5,000</div>
<div><span style="background-color: #E6B71E"></span>1,000</div>
<div><span style="background-color: #EED322"></span>100</div>
<div><span style="background-color: #F2F12D"></span>0</div>
</div>
 
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	mapboxgl.accessToken = '<your access token here>';
var map = new mapboxgl.Map({
container: 'map',
style: 'mapbox://styles/mapbox/light-v10',
center: [-98, 38.88],
minZoom: 3,
zoom: 3
});
 
var zoomThreshold = 4;
 
map.on('load', function() {
map.addSource('population', {
'type': 'vector',
'url': 'mapbox://mapbox.660ui7x6'
});
 
map.addLayer(
{
'id': 'state-population',
'source': 'population',
'source-layer': 'state_county_population_2014_cen',
'maxzoom': zoomThreshold,
'type': 'fill',
'filter': ['==', 'isState', true],
'paint': {
'fill-color': [
'interpolate',
['linear'],
['get', 'population'],
0,
'#F2F12D',
500000,
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750000,
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1000000,
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2500000,
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5000000,
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7500000,
'#A25626',
10000000,
'#8B4225',
25000000,
'#723122'
],
'fill-opacity': 0.75
}
},
'waterway-label'
);
 
map.addLayer(
{
'id': 'county-population',
'source': 'population',
'source-layer': 'state_county_population_2014_cen',
'minzoom': zoomThreshold,
'type': 'fill',
'filter': ['==', 'isCounty', true],
'paint': {
'fill-color': [
'interpolate',
['linear'],
['get', 'population'],
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'fill-opacity': 0.75
}
},
'waterway-label'
);
});
 
var stateLegendEl = document.getElementById('state-legend');
var countyLegendEl = document.getElementById('county-legend');
map.on('zoom', function() {
if (map.getZoom() > zoomThreshold) {
stateLegendEl.style.display = 'none';
countyLegendEl.style.display = 'block';
} else {
stateLegendEl.style.display = 'block';
countyLegendEl.style.display = 'none';
}
});
</script>
 
</body>
</html>