Generating Baidu Map Heatmaps with PHP

1. Preparation

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

2. Import Baidu Map API

Download the Baidu Map API library, place it in your project (e.g., under the vendor directory), and include it in your PHP code:

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

3. Prepare Heatmap Data

Prepare the data as an array of latitude, longitude, and weight values. Example:

$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, set basic parameters, and add each point:

$heatmap = new HeatMap();  // create instance
$heatmap->setScale(3);      // weight scaling
$heatmap->setOpacity(0.8);   // transparency

foreach ($heatPoints as $point) {
    $heatmap->addPoint($point['lng'], $point['lat'], $point['count']);
}
$heatmapData = $heatmap->getHeatMapImage(); // get heatmap image data

5. Display the Heatmap

In the HTML page, add a map container and use JavaScript to create a Baidu Map instance, add a HeatmapOverlay, and set the data:

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);
map.addOverlay(heatmapOverlay);
heatmapOverlay.setDataSet({ data: <?php echo json_encode($heatmapData); ?> });

Following these steps, you can easily generate and display a heatmap in a PHP project, visualizing data density with color gradients.