Generating Heatmaps with Baidu Maps API in PHP

Heatmaps visualize data density by using color gradients. This article demonstrates how to create and display heatmaps in a PHP project by leveraging the Baidu Maps API.

1. Preparation

Before starting, obtain a Baidu Maps developer account, create an application, and apply for an API access key on the Baidu Maps Open Platform.

2. Import Baidu Maps API

Download the Baidu Maps API library, extract it, and place the folder (e.g., under vendor ) in your project. Then include the autoloader in your PHP code:

require 'vendor/bdmapapi-master/autoload.php';
use BaiduMapAPIHeatMapHeatMap;

3. Prepare Heatmap Data

Collect latitude, longitude, and weight values for each point, storing them in a two‑dimensional array $heatPoints :

$heatPoints = [
    ['lng' => 113.943062, 'lat' => 22.549006, 'count' => 10],
    ['lng' => 114.064871, 'lat' => 22.548925, 'count' => 20],
    ['lng' => 113.88908,  'lat' => 22.580623, 'count' => 30],
    // more points …
];

4. Generate Heatmap Data

Create a HeatMap instance and configure basic parameters such as scale and opacity:

$heatmap = new HeatMap();
$heatmap->setScale(3);      // weight scaling factor
$heatmap->setOpacity(0.8);   // heatmap opacity

Iterate over $heatPoints and add each point to the heatmap:

foreach ($heatPoints as $point) {
    $heatmap->addPoint($point['lng'], $point['lat'], $point['count']);
}

Finally, obtain the heatmap image data:

$heatmapData = $heatmap->getHeatMapImage();

5. Display the Heatmap

In the HTML page, create a map container <div id="map"></div> and load the Baidu Maps JavaScript API. After the page loads, instantiate the map and add a heatmap overlay:

var map = new BMap.Map("map"); // create map instance
var heatmapOverlay = new BMapLib.HeatmapOverlay(); // heatmap overlay
map.centerAndZoom(new BMap.Point(113.943062, 22.549006), 13); // set center and zoom
map.addOverlay(heatmapOverlay); // add overlay
heatmapOverlay.setDataSet({ data:
}); // set data

With these steps, you can generate and render a heatmap in a PHP project, allowing you to visualize data density effectively.

Conclusion

The guide shows how to combine PHP with the Baidu Maps API to produce heatmap visualizations, providing complete code snippets for data preparation, heatmap generation, and front‑end display, helping developers quickly integrate this feature into their applications.