Generating Baidu Map Heatmaps with PHP

Heatmaps are visualizations that use color gradients to represent data density. In PHP we can leverage the Baidu Map API to generate and display such heatmaps.

1. Preparation

Before starting, ensure you have a Baidu Map developer account, have created an application, and obtained an API access key from the Baidu Map Open Platform.

2. Include Baidu Map API

Download the Baidu Map API library, unzip it, and place the folder (e.g., under vendor ) in your project. Then require the autoloader and import the HeatMap class:

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

3. Prepare Heatmap Data

Collect the data points you want to visualize. Each point should contain longitude ( lng ), latitude ( lat ) and a weight ( count ). Example PHP array:

<code>$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 …
];
</code>

4. Generate Heatmap Data

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

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

Add each point to the heatmap using addPoint :

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

Finally, obtain the heatmap image data:

<code>$heatmapData = $heatmap->getHeatMapImage();
</code>

5. Display the Heatmap

In your HTML page, create a container for the map:

<code>&lt;div id="map"&gt;&lt;/div&gt;
</code>

Then, using JavaScript, instantiate the Baidu Map, add a heatmap overlay, and feed the generated data:

<code>var map = new BMap.Map("map"); // create map instance
var heatmapOverlay = new BMapLib.HeatmapOverlay(); // create overlay
map.centerAndZoom(new BMap.Point(113.943062, 22.549006), 13); // set center and zoom
map.addOverlay(heatmapOverlay); // add overlay
heatmapOverlay.setDataSet({ data: <?php echo json_encode($heatmapData); ?> }); // set data
</code>

By following these steps you can easily generate and display a Baidu Map heatmap in a PHP project, turning raw coordinate‑weight data into an intuitive visual representation.

Conclusion

This article demonstrated how to combine PHP with the Baidu Map API to create heatmap visualizations, providing complete code snippets for data preparation, heatmap generation, and front‑end display, helping developers quickly add density‑based maps to their applications.