A drone is used to map difficult transition spaces within buildings such as staircases between different levels of a multi-level building. The mapping technique used may vary based on the type of building space. For instance, for linear staircases, an orthogonal trajectory path or a smooth trajectory path may be used to map the transition space. The orthogonal trajectory path and the smooth trajectory path may be derived, at least in part, on initial and terminating points provided by a user. For circular staircases, a user may move the drone from the initial point to the terminating point, and the drone may determine a trajectory path based on the user's movement of the drone from the initial point to the terminating point.