UAVs are capable of flying at very low altitudes, at which airplanes are not permitted (e.g. 80 metres). As a result UAVs can be deployed for topography, by which very exact results can be achieved. UAVs are ideally suited to urban areas, working in medium- to large-scale areas, remote areas, or places that are difficult to access. Their usage saves time compared to what would be possible with topographical methods. On top of which they are a very cost effective option.