Openlayers 如何在热图中显示计数而不是大小?
我正在尝试实现以下openlayers热图示例: 是否可以显示计数(同一区域内有多少个点),而不是大小 编辑: 缩小时指针计数和显示:Openlayers 如何在热图中显示计数而不是大小?,openlayers,openlayers-5,Openlayers,Openlayers 5,我正在尝试实现以下openlayers热图示例: 是否可以显示计数(同一区域内有多少个点),而不是大小 编辑: 缩小时指针计数和显示: 如果您的意思是将群集功能显示为热图,则可以这样做。这是群集功能示例和热图示例的组合 <!DOCTYPE html> <html> <head> <title>Clustered Features</title> <link rel="stylesheet" href="htt
如果您的意思是将群集功能显示为热图,则可以这样做。这是群集功能示例和热图示例的组合
<!DOCTYPE html>
<html>
<head>
<title>Clustered Features</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.6.5/css/ol.css" type="text/css">
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.6.5/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<form>
<label>cluster distance</label>
<input id="distance" type="range" min="0" max="100" step="1" value="40"/>
<label>radius size</label>
<input id="radius" type="range" min="1" max="50" step="1" value="5"/>
<label>blur size</label>
<input id="blur" type="range" min="1" max="50" step="1" value="15"/>
</form>
<script>
var distance = document.getElementById('distance');
var blur = document.getElementById('blur');
var radius = document.getElementById('radius');
var count = 20000;
var features = new Array(count);
var e = 4500000;
for (var i = 0; i < count; ++i) {
var coordinates = [2 * e * Math.random() - e, 2 * e * Math.random() - e];
features[i] = new ol.Feature(new ol.geom.Point(coordinates));
}
var source = new ol.source.Vector({
features: features
});
var clusterSource = new ol.source.Cluster({
distance: parseInt(distance.value, 10),
source: source
});
var styleCache = {};
var vector = new ol.layer.Heatmap({
source: clusterSource,
weight: function(feature) { return feature.get('features').length/1000; },
blur: parseInt(blur.value, 10),
radius: parseInt(radius.value, 10)
});
var raster = new ol.layer.Tile({
source: new ol.source.OSM()
});
var map = new ol.Map({
layers: [raster, vector],
target: 'map',
view: new ol.View({
center: [0, 0],
zoom: 2
})
});
distance.addEventListener('input', function() {
clusterSource.setDistance(parseInt(distance.value, 10));
});
blur.addEventListener('input', function() {
vector.setBlur(parseInt(blur.value, 10));
});
radius.addEventListener('input', function() {
vector.setRadius(parseInt(radius.value, 10));
});
</script>
</body>
</html>
如果您的意思是将群集功能显示为热图,则可以这样做。这是群集功能示例和热图示例的组合
<!DOCTYPE html>
<html>
<head>
<title>Clustered Features</title>
<link rel="stylesheet" href="https://openlayers.org/en/v4.6.5/css/ol.css" type="text/css">
<!-- The line below is only needed for old environments like Internet Explorer and Android 4.x -->
<script src="https://cdn.polyfill.io/v2/polyfill.min.js?features=requestAnimationFrame,Element.prototype.classList,URL"></script>
<script src="https://openlayers.org/en/v4.6.5/build/ol.js"></script>
</head>
<body>
<div id="map" class="map"></div>
<form>
<label>cluster distance</label>
<input id="distance" type="range" min="0" max="100" step="1" value="40"/>
<label>radius size</label>
<input id="radius" type="range" min="1" max="50" step="1" value="5"/>
<label>blur size</label>
<input id="blur" type="range" min="1" max="50" step="1" value="15"/>
</form>
<script>
var distance = document.getElementById('distance');
var blur = document.getElementById('blur');
var radius = document.getElementById('radius');
var count = 20000;
var features = new Array(count);
var e = 4500000;
for (var i = 0; i < count; ++i) {
var coordinates = [2 * e * Math.random() - e, 2 * e * Math.random() - e];
features[i] = new ol.Feature(new ol.geom.Point(coordinates));
}
var source = new ol.source.Vector({
features: features
});
var clusterSource = new ol.source.Cluster({
distance: parseInt(distance.value, 10),
source: source
});
var styleCache = {};
var vector = new ol.layer.Heatmap({
source: clusterSource,
weight: function(feature) { return feature.get('features').length/1000; },
blur: parseInt(blur.value, 10),
radius: parseInt(radius.value, 10)
});
var raster = new ol.layer.Tile({
source: new ol.source.OSM()
});
var map = new ol.Map({
layers: [raster, vector],
target: 'map',
view: new ol.View({
center: [0, 0],
zoom: 2
})
});
distance.addEventListener('input', function() {
clusterSource.setDistance(parseInt(distance.value, 10));
});
blur.addEventListener('input', function() {
vector.setBlur(parseInt(blur.value, 10));
});
radius.addEventListener('input', function() {
vector.setRadius(parseInt(radius.value, 10));
});
</script>
</body>
</html>
嗨@Mike,非常感谢你的回复。我使用的群集功能与您的示例相同,但希望在缩小时在同一区域显示点计数器,我添加了一个图像作为示例。请检查我编辑的部分。您需要使用clusterSource的两个图层,如上所述的热图和带有样式功能的法线向量层,如openlayers示例中的集群特征。在热图选项中指定maxResolution,并为另一层指定与minResolution相同的值。请更新代码以反映与您所说的相同的值,我会接受你的回答。我已经实现了你的代码,但是当我为cluster layer添加minResolution和为heatmap layer添加maxResolution时,只有heatmap layer工作,而不是具有计数样式的clusters layer,但是当我从clusters中删除minResolution时,倒计时样式工作,但heatmap不工作,发生这种事情的原因可能是什么?我发现我的视图设置有这样的问题:中心:maxZoom:19,zoom:8,minZoom:3,我也需要这些值集,所以在这种情况下需要做什么?嗨@Mike,非常感谢你的回复。我使用的群集功能与您的示例相同,但希望在缩小时在同一区域显示点计数器,我添加了一个图像作为示例。请检查我编辑的部分。您需要使用clusterSource的两个图层,如上所述的热图和带有样式功能的法线向量层,如openlayers示例中的集群特征。在热图选项中指定maxResolution,并为另一层指定与minResolution相同的值。请更新代码以反映与您所说的相同的值,我会接受你的回答。我已经实现了你的代码,但是当我为cluster layer添加minResolution和为heatmap layer添加maxResolution时,只有heatmap layer工作,而不是具有计数样式的clusters layer,但是当我从clusters中删除minResolution时,倒计时样式工作,但heatmap不工作,发生这种情况的原因可能是什么?我发现视图设置的问题是:中心:maxZoom:19,zoom:8,minZoom:3,我还需要这些值集,那么在这种情况下需要做什么?
weight: function(feature) {
var maxSize = 0;
clusterSource.forEachFeature( function(feature) { maxSize = Math.max(maxSize, feature.get('features').length); } );
return feature.get('features').length/maxSize;
},