Generating Heatmaps with Baidu Map API in PHP

Heatmaps visualize data density through color gradients, and this article shows how to generate and display them in a PHP project using the Baidu Map API.

Before starting, obtain a Baidu Map developer account, create an application, and acquire an API access key.

Import the Baidu Map API library into your PHP project:

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

Prepare the heat‑map data as an array of latitude, longitude and weight values (e.g., $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 …
];

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

$heatmap = new HeatMap();
$heatmap->setScale(3);
$heatmap->setOpacity(0.8);

Add each point to the heat‑map using addPoint:

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

Generate the heat‑map image data: $heatmapData = $heatmap->getHeatMapImage(); Finally, display the heat‑map on a web page. Add a map container and use JavaScript to create a Baidu Map instance, add a heat‑map overlay, and set the data set:

var map = new BMap.Map("map");
var heatmapOverlay = new BMapLib.HeatmapOverlay();
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 render heatmaps in a PHP project, allowing you to visualize data density with gradient colors for better analysis.