Certain examples described herein relate to estimating dimensions of an enclosed space such as a room using a monocular multi-directional camera device. In examples, a movement of the camera device around a point in a plane of movement is performed, such as by a robotic device. Using the monocular multi-directional camera device, a sequence of images are obtained at a plurality of different angular positions during the movement. Pose data is determined from the sequence of images. The pose data is determined using a set of features detected within the sequence of images. Depth values are then estimated by evaluating a volumetric function of the sequence of images and the pose data. A three dimensional volume is defined around a reference position of the camera device, wherein the three-dimensional volume has a two-dimensional polygonal cross-section within the plane of movement. The three dimensional volume is then fitted to the depth values to determine dimensions for the polygonal cross-section. These dimensions then provide an estimate for the shape of the enclosed space.