How to use JS and Amap to implement location aggregation function

How to use JS and Amap to implement point aggregation function

With the development of the Internet, map applications have become an indispensable part of our daily lives. In map applications, a large amount of location information often needs to be processed, and the location point aggregation function can effectively display this information and improve user experience. This article will introduce how to use JS and Amap API to implement location aggregation function, and give specific code examples.

1. Preparation work

Before we start writing code, we need to do some preparation work:

1. Register an AutoNavi developer account and create an application to obtain the API Key. First, we need to register an AutoNavi developer account and create an application. After successfully creating the application, you will get an API Key, which will be used to call the Amap API on the web page.
2. Reference the JS file of Amap. Introduce the JS file of Amap into the web page so that we can use the map function in it. You can introduce the JS file by adding the following code to the web page:

<script src="http://webapi.amap.com/maps?v=1.4.15&key=your-api-key"></script>

where, your-api-key is the API Key obtained previously and needs to be replaced with your own Key.

2. Create a map

Before implementing the location point aggregation function, we first need to create a map in the web page. You can use the following code to create a basic map:

<div id="mapContainer"></div>

<script>
    var map = new AMap.Map('mapContainer', {
        zoom: 11,  // 地图缩放级别
        center: [116.397428, 39.90923]  // 地图中心点坐标
    });
</script>

In the above code, we create a div element with the id "mapContainer" and use the AMap.Map class to create a map instance. Zoom represents the zoom level of the map. The larger the zoom level, the smaller the map display range; center represents the coordinates of the center point of the map. Here, we set the map center point as the coordinates of Beijing City.

3. Add location

Next, we need to add some location information to the map. The following code example can be used:

<script>
    var markers = [
        {
            position: [116.410049, 39.916871],  // 地点坐标
            name: '地点1'  // 地点名称
        },
        {
            position: [116.491874, 39.913187],
            name: '地点2'
        },
        // ...
    ];
    
    for (var i = 0; i < markers.length; i++) {
        var marker = new AMap.Marker({
            map: map,
            position: markers[i].position
        });
        marker.setTitle(markers[i].name);
    }
</script>

In the above code, we create a markers array to store the location and name information of the place. Then, each location is displayed on the map by looping through the markers array. Use the AMap.Marker class to create a location marker, specify the map instance by setting the map attribute, and set the location coordinates by setting the position attribute. Finally, use the setTitle method to set the location name.

4. Implement point aggregation function

Through the above steps, we can already display multiple locations on the map. Next, we will further implement the function of location point aggregation.

First, you need to reference the AMap.MarkerClusterer library file. You can add the following code to the web page:

<script src="http://webapi.amap.com/ui/1.1/main.js"></script>

Then, use the following code to implement the point aggregation function:

<script>
    var cluster = new AMap.MarkerClusterer(map, markers, {
        gridSize: 60,  // 聚合的网格大小
        averageCenter: true,  // 聚合点的中心位置取平均值
        maxZoom: 16  // 最大缩放级别
    });
    
    cluster.setMap(map);
</script>

In the above code, we use the AMap.MarkerClusterer class to create an aggregation object, Specify the map instance by setting the map attribute, and specify the array of location markers to be aggregated by setting the markers attribute. You can adjust the aggregated grid size by setting the gridSize attribute. The larger the value, the smaller the aggregation range; by setting the averageCenter attribute to specify the center position of the aggregation point for averaging; by setting the maxZoom attribute to specify the maximum zoom level to achieve the maximum zoom After the level, aggregation will no longer occur. Finally, use the setMap method to add the aggregate object to the map.

5. Summary

Through the above steps, we have successfully implemented the function of location point aggregation. During use, you can adjust the parameter values ​​in the code according to your own needs to adapt to different scenarios. At the same time, Amap also provides other rich API functions, such as geocoding, route planning, etc., which can be flexibly called as needed. I hope this article can be helpful to everyone in implementing the location aggregation function.

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