添加实时数据

添加实时GeoJSON数据到地图;

<!DOCTYPE html>
<html lang="en">
<head>
    <title>添加实时数据</title>
    <meta property="og:description" content="添加实时GeoJSON数据到地图" />
    <meta charset='utf-8'>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel='stylesheet' href='https://unpkg.com/maplibre-gl@5.5.0/dist/maplibre-gl.css' />
    <script src='https://unpkg.com/maplibre-gl@5.5.0/dist/maplibre-gl.js'></script>
    <style>
        body { margin: 0; padding: 0; }
        html, body, #map { height: 100%; }
        .map-overlay {
            position: absolute;
            bottom: 0;
            right: 0;
            background: rgba(255, 255, 255, 0.8);
            margin-right: 20px;
            font-family: 'Open Sans', sans-serif;
            overflow: auto;
            border-radius: 3px;
            padding: 10px;
            box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
            line-height: 24px;
            max-width: 300px;
            color: #222;
        }
        .legend {
            background-color: #fff;
            border-radius: 3px;
            bottom: 30px;
            box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
            padding: 10px;
        }
        .legend h4 {
            margin: 0 0 10px;
        }
        .legend div span {
            border-radius: 50%;
            display: inline-block;
            height: 10px;
            margin-right: 5px;
            width: 10px;
        }
        .updateTime {
            font-size: 12px;
            font-style: italic;
            margin-top: 10px;
        }
    </style>
</head>
<body>
<div id="map"></div>
<div class="map-overlay legend">
    <h4>美国地震实时数据</h4>
    <div><span style="background-color: #f00"></span>震级 6+</div>
    <div><span style="background-color: #fd5"></span>震级 5+</div>
    <div><span style="background-color: #ff0"></span>震级 4+</div>
    <div><span style="background-color: #0f0"></span>震级 3+</div>
    <div><span style="background-color: #0ff"></span>震级 2+</div>
    <div><span style="background-color: #06f"></span>震级 1+</div>
    <div><span style="background-color: #f0f"></span>震级 0+</div>
    <div id="updateTime" class="updateTime"></div>
</div>
<script>
    const map = new maplibregl.Map({
        container: 'map',
        style: 'https://api.maptiler.com/maps/streets/style.json?key=get_your_own_OpIi9ZULNHzrESv6T2vL',
        center: [-100, 40],
        zoom: 3
    });

    // 请求实时地震数据的函数
    function getEarthquakeData() {
        // 使用USGS的地震数据API
        return fetch('https://earthquake.usgs.gov/earthquakes/feed/v1.0/summary/all_day.geojson')
            .then(response => response.json())
            .catch(error => {
                console.error('获取地震数据失败:', error);
                return null;
            });
    }

    // 更新地图上的地震数据
    function updateEarthquakes() {
        getEarthquakeData().then(data => {
            if (!data) return;

            // 更新最后更新时间
            const updateTimeElement = document.getElementById('updateTime');
            const now = new Date();
            updateTimeElement.textContent = `上次更新: ${now.toLocaleTimeString()}`;

            // 如果数据源已存在，直接更新数据
            if (map.getSource('earthquakes')) {
                map.getSource('earthquakes').setData(data);
            } else {
                // 首次加载时，创建数据源和图层
                map.addSource('earthquakes', {
                    'type': 'geojson',
                    'data': data
                });

                map.addLayer({
                    'id': 'earthquakes-circle',
                    'type': 'circle',
                    'source': 'earthquakes',
                    'paint': {
                        'circle-radius': [
                            'interpolate',
                            ['linear'],
                            ['get', 'mag'],
                            0, 4,
                            6, 16
                        ],
                        'circle-color': [
                            'interpolate',
                            ['linear'],
                            ['get', 'mag'],
                            0, '#f0f',
                            1, '#06f',
                            2, '#0ff',
                            3, '#0f0',
                            4, '#ff0',
                            5, '#fd5',
                            6, '#f00'
                        ],
                        'circle-opacity': 0.75,
                        'circle-stroke-width': 1,
                        'circle-stroke-color': '#fff'
                    }
                });

                // 添加鼠标悬停交互
                map.on('mouseenter', 'earthquakes-circle', () => {
                    map.getCanvas().style.cursor = 'pointer';
                });
                map.on('mouseleave', 'earthquakes-circle', () => {
                    map.getCanvas().style.cursor = '';
                });

                // 添加点击事件显示弹出窗口
                map.on('click', 'earthquakes-circle', (e) => {
                    const coordinates = e.features[0].geometry.coordinates.slice();
                    const magnitude = e.features[0].properties.mag;
                    const place = e.features[0].properties.place;
                    const time = new Date(e.features[0].properties.time).toLocaleString();
                    
                    new maplibregl.Popup()
                        .setLngLat(coordinates)
                        .setHTML(`<h3>震级 ${magnitude}</h3><p>${place}</p><p>时间: ${time}</p>`)
                        .addTo(map);
                });
            }
        });
    }

    map.on('load', () => {
        // 初始加载地震数据
        updateEarthquakes();
        
        // 每隔5分钟更新一次数据
        setInterval(updateEarthquakes, 5 * 60 * 1000);
    });
</script>
</body>
</html>