Generating Baidu Map Heatmaps with PHP

Heatmap is a visualization that uses color gradients to show data density. Using PHP and Baidu Map API, you can generate and display such heatmaps.

1. Preparation

Obtain a Baidu Map developer account, create an application, and acquire an API key.

2. Import Baidu Map API

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

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

3. Prepare Heatmap Data

Collect latitude, longitude, and weight values into an array, for 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 scale and opacity, then 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();

5. Display the Heatmap

In the HTML page, add a map container and use JavaScript to create a Baidu Map instance and overlay the heatmap 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 embed a Baidu Map heatmap in any PHP project, allowing you to visualize data density with gradient colors.