A method of controlling an autonomous vehicle , comprising: obtaining map data (510i; 810) including a three dimensional, 3-D, point cloud representing a perspective of a sensor on a mapping vehicle ; capturing point-cloud data (502i; 802) representative of a surrounding environment of the autonomous vehicle with one or more light detection and ranging, LIDAR, sensors , each point in the point-cloud data representing a reflection from the surrounding environment; determining a position of the autonomous vehicle in the area mapped by the mapping vehicle based on an overlap score (552; 554) and the map data (510i; 810); and controlling the autonomous vehicle based on the position; characterized by identifying a first point in the point cloud data as a non-matching point by aligning the captured point cloud data with the map data and determining that there is no point in the map data having equivalent coordinates to the first point; determining whether the non-matching point is to be used in a determination of the overlap score (552; 554) based on one or more comparisons of the point cloud data and the map data, the overlap score being a ratio of a number of points in the point cloud data that match points in the map data, to a total number of points in the point cloud data, wherein if the non-matching point is not included in the overlap score, the total number of points does not include the non-matching point; determining the overlap score based at least partly on the determining that the non-matching point is to be used in the determination of the overlap score, the overlap score being determined by determining a ratio between (i) the number of points in the point cloud data that match points in the map data and (ii) the total number of points in the point cloud data obtaining map data (510i; 810) including a three dimensional, 3-D, point cloud representing a perspective of a sensor on a mapping vehicle ; capturing point-cloud data (502i; 802) representative of a surrounding environment of the autonomous vehicle with one or more light detection and ranging, LIDAR, sensors , each point in the point-cloud data representing a reflection from the surrounding environment; determining a position of the autonomous vehicle in the area mapped by the mapping vehicle based on an overlap score (552; 554) and the map data (510i; 810); and controlling the autonomous vehicle based on the position; characterized by identifying a first point in the point cloud data as a non-matching point by aligning the captured point cloud data with the map data and determining that there is no point in the map data having equivalent coordinates to the first point; determining whether the non-matching point is to be used in a determination of the overlap score (552; 554) based on one or more comparisons of the point cloud data and the map data, the overlap score being a ratio of a number of points in the point cloud data that match points in the map data, to a total number of points in the point cloud data, wherein if the non-matching point is not included in the overlap score, the total number of points does not include the non-matching point; determining the overlap score based at least partly on the determining that the non-matching point is to be used in the determination of the overlap score, the overlap score being determined by determining a ratio between (i) the number of points in the point cloud data that match points in the map data and (ii) the total number of points in the point cloud data <EOS>