Using JavaScript and Tencent Maps to implement map polygon drawing function

Use JavaScript and Tencent Maps to implement map polygon drawing function

Tencent Maps is a practical map service API developed by Tencent, which provides a wealth of Map display and interactive functions. When developing web applications, you can use the API provided by Tencent Maps to complete various map-related requirements. This article will introduce how to use JavaScript and Tencent Map API to implement the map polygon drawing function, and provide specific code examples.

Step 1: Introduce Tencent Map API

Add the following code to the

tag in the HTML file:

<script src="https://map.qq.com/api/js?v=2.exp&key=YOUR_API_KEY"></script>

Replace YOUR_API_KEY with your Tencent Map API key applied for on the open platform.

Step 2: Create a map container

Add the following code to the tag in the HTML file:

<div id="map"></div>

The id here is "map", You can name it as needed.

Step 3: Initialize the map

In the JavaScript file, use the following code to initialize the map:

var map = new qq.maps.Map(document.getElementById("map"), {
    center: new qq.maps.LatLng(39.916527, 116.397128),
    zoom: 13
});

The latitude and longitude here represents the initial center point location and zoom level of the map . It can be adjusted according to actual needs.

Step 4: Draw the polygon

In the JavaScript file, use the following code to draw the polygon:

var polygon = new qq.maps.Polygon({
    path: [
        new qq.maps.LatLng(39.919527, 116.393128),
        new qq.maps.LatLng(39.915527, 116.397128),
        new qq.maps.LatLng(39.913527, 116.394128)
    ],
    strokeColor: new qq.maps.Color(0, 0, 0, 0.5),
    fillColor: new qq.maps.Color(0, 0, 0, 0.3),
    strokeWeight: 2,
    editable: true,
    map: map
});

The above code creates a polygon containing three vertices and sets The border color, fill color, border line width, editability, and map instance are included.

Step 5: Listen to polygon editing events

If you want to trigger some operations when the user edits a polygon, you can listen to the polygon editing event. The sample code is as follows:

qq.maps.event.addListener(polygon, 'path_changed', function() {
    var path = polygon.getPath();
    console.log("多边形编辑后的顶点坐标：" + path);
});

The above code will print the edited vertex coordinates to the browser's developer tools console when the user edits the vertex coordinates of the polygon.

After completing the above steps, you can draw and edit polygons on Tencent Maps. You can adjust the vertex coordinates and style of the polygon as needed.

Summary:

This article introduces how to use JavaScript and Tencent Map API to implement the map polygon drawing function. First, introduce the Tencent Map API and initialize the map, then create a polygon object and set its vertex coordinates and style. If you need to listen to polygon editing events, you can do it through a listener. I hope this article can help you implement the map polygon drawing function in web application development.

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