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Using JavaScript and Tencent Maps to implement map area selection function

王林Original: 2023-11-21 17:59:151573browse

Using JavaScript and Tencent Maps to implement the map area selection function

The map area selection function is one of the common requirements in modern web applications. This feature allows users to select a specific area by drawing a polygon on the map. This article will introduce how to use JavaScript and Tencent Map API to implement this function, and provide specific code examples.

First, we need to introduce the JavaScript file of Tencent Map API and other necessary resources into the HTML file. Register a developer account on the Tencent Map Open Platform, obtain the developer key, and replace it with YOUR_API_KEY in the following code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>地图区域选择</title>
  <style>
    #mapContainer {
      height: 500px;
      width: 100%;
    }
  </style>
</head>
<body>
  <div id="mapContainer"></div>
  <script src="https://map.qq.com/api/js?v=2.exp&key=YOUR_API_KEY"></script>
  <script src="https://open.mobile.qq.com/sdk/qqapi.js"></script>
  <script src="script.js"></script>
</body>
</html>

Next, we will write in the JavaScript file script.js to implement map area selection function code. First, we need to initialize the map, create a map object, and add it to the mapContainer element in the web page:

var map = new qq.maps.Map(document.getElementById('mapContainer'), {
  center: new qq.maps.LatLng(39.916527, 116.397128),
  zoom: 12
});

Then, we need to add an event listener to the map when the user clicks the mouse on the map , start drawing polygons. During the drawing process, the shape of the polygon can be changed by dragging the mouse. When the user releases the mouse, the drawing process ends and a callback function is triggered:

var drawingManager = new qq.maps.drawing.DrawingManager({
  map: map,
  drawingMode: qq.maps.drawing.OverlayType.POLYGON,
  polygonOptions: {
    fillColor: qq.maps.Color.fromHex('#0088ff', 0.3),
    strokeColor: qq.maps.Color.fromHex('#0088ff', 0.8),
    strokeWeight: 2
  }
});
qq.maps.event.addListener(drawingManager, 'polygoncomplete', function (polygon) {
  var path = polygon.getPath();
  var area = qq.maps.geometry.spherical.computeArea(path);
  console.log("所选区域面积为：" + area + "平方米");
});

In the callback function, we obtain the path of the polygon, and then use the geometric calculation function computeArea provided by Tencent Map API to calculate the area of the polygon , and output the area value on the console.

Finally, we can process the data in the selected area according to actual needs. For example, sending it to the server for further processing, or displaying relevant information on the user interface.

The above are the basic steps and code examples for using JavaScript and Tencent Map API to implement the map area selection function. You can make appropriate modifications and extensions according to your needs. Hope this article can be helpful to you!

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