1. A method, comprising: determining a depth map of at least one static surface of a building; determining a plurality of surface contours in the depth map, wherein each of the plurality of surface contours comprises a group of connected points showing changing surface depth along the at least one static surface; receiving sensor data from one or more sensors on a robotic device that is located in the building, wherein the received sensor data is indicative of the at least one static surface of the building; determining, based on the received sensor data, a plurality of respective distances between the robotic device and a plurality of respective detected points on the at least one static surface of the building; identifying at least one surface contour that includes the plurality of respective detected points on the at least one static surface of the building; determining, for the at least one identified surface contour, at least one corresonding surface contour from the plurality of surface contours in the depth map such that the at least one identified surface contour and the at least one corresponding surface contour have matching changes in surface depth; and determining, based on the plurality of respective distances, a position of the robotic device in the building that aligns the at least one identified surface contour with the at least one corresponding surface contour in the depth map of the at least one static surface of the building.