openlayers-方向标注
需求
给LineString 标注方向
效果图
设计思路
设计一个方向箭头图标
计算线段方向（LineString 可以放很多坐标而线段方向是两点之间）
（0，1）（1，2）（2，3）…方式计算每一段的方向角度
方向点安放坐标
let array_coor = lineStringForl.getCoordinateAt(i * 1.0 / res);
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主要函数
单一线段计算角度
function calcD(start, end) {
let dx = end[0] - start[0];
let dy = end[1] - start[1];
let rotation = Math.atan2(dy, dx);
console.log("角度" + rotation);
return rotation;
}
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从坐标组中计算线段以及每一段的方向角
// 计算线段角度
function calcLineStringD(coordis) {
let n = coordis.length;
let vs = [];
for (let i = 0; i < n; i++) {
if (i + 1 < n) {
vs.push({
"line": [coordis[i], coordis[i + 1]],
"d": calcD(coordis[i], coordis[i + 1])
})
}
}
return vs;
}
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设置样式
new ol.style.Style({
geometry: new ol.geom.Point(array_coor),
image: new ol.style.Icon({
src: 'http://localhost:9999/titles/fx.png',
anchor: [0.75, 0.5],
rotateWithView: true,
rotation: -rat
})
})
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完整demo
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>方向箭头</title>
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"
integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN"
crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js"
integrity="sha384-b/U6ypiBEHpOf/4+1nzFpr53nxSS+GLCkfwBdFNTxtclqqenISfwAzpKaMNFNmj4"
crossorigin="anonymous"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js"
integrity="sha384-h0AbiXch4ZDo7tp9hKZ4TsHbi047NrKGLO3SEJAg45jXxnGIfYzk4Si90RDIqNm1"
crossorigin="anonymous"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/openlayers/4.6.5/ol.css"
integrity="sha256-rQq4Fxpq3LlPQ8yP11i6Z2lAo82b6ACDgd35CKyNEBw=" crossorigin="anonymous"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/openlayers/4.6.5/ol.js"
integrity="sha256-77IKwU93jwIX7zmgEBfYGHcmeO0Fx2MoWB/ooh9QkBA="
crossorigin="anonymous"></script>
<script src="https://unpkg.com/rbush@2.0.1/rbush.min.js"></script>
</head>
<body>
<div id="map"></div>
<script>
var wkt = 'LineString( 120 30 , 121 31 ,121 32 ,122 33 )';
var format = new ol.format.WKT();
var feature = format.readFeature(wkt, {});
// 将方向标注放在线段中间
function direction_labeling_02(res, lineStringForl, coordis, vs, styles) {
for (let i = 0; i < vs.length; i++) {
let line = vs[i]['line'];
let start =line[0];
let end = line[1];
let array_coor = [
(start[0]+end[0])/2, (start[1]+end[1])/2
];
let d = vs[i]['d'];
styles.push(new ol.style.Style({
geometry: new ol.geom.Point(array_coor),
image: new ol.style.Icon({
src: 'http://localhost:9999/titles/fx.png',
anchor: [0.75, 0.5],
rotateWithView: true,
rotation: -d
})
}))
}
}
function direction_labeling_01(res, lineStringForl, coordis, vs, styles) {
// 这个地方可以修改成你要的箭头数量
let arrow_count = res * 1.0 * 40;
for (let i = 0; i < arrow_count; i++) {
// 求坐标
let array_coor = lineStringForl.getCoordinateAt(i * 1.0 / res);
// // array_coor 在 coordis 不显示
if (inc(coordis, array_coor)) {
console.log("相同" + i);
continue;
}
let rat = calcLinePointD(vs, array_coor);
// 根据 array_coor 在那一条线段上设置 旋转角度
styles.push(new ol.style.Style({
geometry: new ol.geom.Point(array_coor),
image: new ol.style.Icon({
src: 'http://localhost:9999/titles/fx.png',
anchor: [0.75, 0.5],
rotateWithView: true,
rotation: -rat
})
}));
}
}
/**
*
* @param feature feature
* @param res 总共多少个箭头
* @returns {ol.style.Style[]}
*/
function styleFunction(feature, res) {
var lineStringForl = feature.getGeometry();
var coordis = lineStringForl.getCoordinates();
var styles = [
new ol.style.Style({
stroke: new ol.style.Stroke({
color: '#23218b',
width: 10
})
})
];
// 计算线段角度
let vs = calcLineStringD(coordis);
// direction_labeling_01(res, lineStringForl, coordis, vs, styles);
direction_labeling_02(res, lineStringForl, coordis, vs, styles);
return styles;
}
// 计算点是否在线上
function pointInLine(line, Q) {
let pi = line[0];
let pj = line[1];
if ((Q[0] - pi[0]) * (pj[1] - pi[1]) == (pj[0] - pi[0]) * (Q[1] - pi[1]) && Math.min(pi[0], pj[0])
<= Q[0] && Q[0] <= Math.max(pi[0], pj[0]) && Math.min(pi[1], pj[1]) <= Q[1] && Q[1] <= Math.max(pi[1],
pj[1])) {
console.log("再线段上");
return true;
} else {
console.log("不再线段上");
return false;
}
}
// 返回点所在线段的具体角度
function calcLinePointD(vs, point) {
for (let i = 0; i < vs.length; i++) {
let line = vs[i]['line'];
let d = vs[i]['d'];
if (pointInLine(line, point) == true) {
return d;
}
}
}
// 计算线段角度
function calcLineStringD(coordis) {
let n = coordis.length;
let vs = [];
for (let i = 0; i < n; i++) {
if (i + 1 < n) {
vs.push({
"line": [coordis[i], coordis[i + 1]],
"d": calcD(coordis[i], coordis[i + 1])
})
}
}
return vs;
}
// 计算线段角度
function calcD(start, end) {
let dx = end[0] - start[0];
let dy = end[1] - start[1];
let rotation = Math.atan2(dy, dx);
console.log("角度" + rotation);
return rotation;
}
/**
* 判断坐标组合cood中是否有atc,
* 不会判断强写
* @param cood 坐标组合
* @param atc 坐标
* @returns {boolean}
*/
function inc(cood, atc) {
for (c in cood) {
if (cood[c][0] == atc[0] && cood[c][1] == atc[1]) {
return true;
}
}
return false;
}
var vector = new ol.layer.Vector({
source: new ol.source.Vector({
features: [feature]
}),
style: styleFunction(feature, 100)
});
var gaodeMapLayer = new ol.layer.Tile({
source: new ol.source.XYZ({
url: 'http://wprd0{1-4}.is.autonavi.com/appmaptile?lang=zh_cn&size=1&style=7&x={x}&y={y}&z={z}'
})
});
var map = new ol.Map({
layers: [gaodeMapLayer, vector],
view: new ol.View({
center: [120, 30],
projection: 'EPSG:4326',
zoom: 5
}),
target: 'map'
});
</script>
</body>
</html>
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版权声明：本文为CSDN博主「staHuri」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/stahuri/article/details/88867365
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