To map the environment, we will need a laser scanner or a depth sensor. Laser scanner data is one of the inputs to the SLAM node. One of the latest depth sensors we can use is the Orbbec Astra Pro (https://orbbec3d.com/product-astra-pro/). You can also use a Kinect for this purpose. Using the depthimage_to_laserscan (http://wiki.ros.org/depthimage_to_laserscan) ROS package, we can convert the depth value to laser scan data.