leaflet读取{"y":115.9057200,"x":29.1660800,"label":0},格式的json文件,在js文件中写名为dbscan的函数绘制leaflet聚类图,用不同的颜色表示不同的类别
时间: 2023-12-10 07:03:43 浏览: 94
以下是一个可能的实现:
```javascript
function dbscan(data, eps, minPts) {
// 初始化每个点的标签为-1,表示未分类
var labels = new Array(data.length).fill(-1);
// 初始化聚类计数器
var clusterCount = 0;
// 计算每对点之间的距离
var distances = [];
for (var i = 0; i < data.length; i++) {
distances[i] = [];
for (var j = 0; j < data.length; j++) {
distances[i][j] = euclideanDistance(data[i], data[j]);
}
}
// 标记每个点是否为核心点,以及它的邻居
var corePoints = [];
var neighbors = [];
for (var i = 0; i < data.length; i++) {
var count = 0;
var indices = [];
for (var j = 0; j < data.length; j++) {
if (distances[i][j] <= eps) {
count++;
indices.push(j);
}
}
if (count >= minPts) {
labels[i] = -2; // 标记为核心点
corePoints.push(i);
neighbors[i] = indices;
}
}
// 迭代计算聚类
for (var i = 0; i < corePoints.length; i++) {
var p = corePoints[i];
if (labels[p] === -2) { // 如果p尚未被分类
clusterCount++;
labels[p] = clusterCount; // 将p标记为新的聚类
expandCluster(p, neighbors[p], clusterCount, labels, distances, eps, minPts);
}
}
return labels;
}
function expandCluster(p, neighbors, clusterCount, labels, distances, eps, minPts) {
for (var i = 0; i < neighbors.length; i++) {
var q = neighbors[i];
if (labels[q] === -2) { // 如果q是核心点且尚未被分类
labels[q] = clusterCount; // 将q加入当前聚类
expandCluster(q, neighbors[q], clusterCount, labels, distances, eps, minPts);
} else if (labels[q] === -1) { // 如果q尚未被分类
labels[q] = clusterCount; // 将q加入当前聚类
}
}
}
function euclideanDistance(a, b) {
var sum = 0;
for (var i = 0; i < a.length; i++) {
sum += Math.pow(a[i] - b[i], 2);
}
return Math.sqrt(sum);
}
// 示例数据
var data = [
{y: 115.9057200, x: 29.1660800, label: 0},
{y: 115.9067200, x: 29.1670800, label: 0},
{y: 115.9067200, x: 29.1660800, label: 0},
{y: 115.9077200, x: 29.1670800, label: 0},
{y: 115.9087200, x: 29.1670800, label: 0},
{y: 116.0000000, x: 30.0000000, label: 1},
{y: 116.0010000, x: 30.0010000, label: 1},
{y: 116.0010000, x: 30.0000000, label: 1},
{y: 116.0020000, x: 30.0010000, label: 1},
{y: 116.0030000, x: 30.0010000, label: 1},
];
// 聚类参数
var eps = 0.01;
var minPts = 2;
// 执行聚类
var labels = dbscan(data.map(d => [d.y, d.x]), eps, minPts);
// 构造颜色映射
var colors = ['blue', 'red', 'green', 'orange', 'purple', 'cyan', 'magenta', 'yellow'];
var colorMap = {};
for (var i = 0; i < labels.length; i++) {
if (labels[i] >= 0) {
if (!colorMap[labels[i]]) {
colorMap[labels[i]] = colors[Object.keys(colorMap).length];
}
}
}
// 在leaflet地图中绘制聚类图
var map = L.map('map').setView([29.1660800, 115.9057200], 15);
L.tileLayer('https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
attribution: 'Map data © <a href="https://www.openstreetmap.org/">OpenStreetMap</a> contributors',
maxZoom: 18
}).addTo(map);
for (var i = 0; i < data.length; i++) {
var marker = L.circleMarker([data[i].y, data[i].x], {
fillColor: colorMap[labels[i]],
fillOpacity: 0.8,
radius: 5,
stroke: false
}).addTo(map);
}
```
这个实现使用了一个简单的欧几里得距离计算函数,递归地扩展每个核心点的聚类,并在每个点上绘制一个由聚类标签颜色映射而来的圆形标记。根据需要,可以调整聚类参数(eps和minPts),以及颜色映射。
阅读全文