Fatal error: Uncaught Error: Class 'Plot' not found in C:\xampp\htdocs\BeiDou_website\z\class\Dgraph\jpgraph\jpgraph_contour.php:387 Stack trace: #0 {main} thrown in C:\xampp\htdocs\BeiDou_website\z\class\Dgraph\jpgraph\jpgraph_contour.php on line 387