A mapping method includes using a first mobile unit to map two-dimensional features while the first mobile unit traverses a surface. Three-dimensional positions of the features are sensed during the mapping. A three-dimensional map is created including associations between the three-dimensional positions of the features and the map of the two-dimensional features. The three-dimensional map is provided from the first mobile unit to a second mobile unit. The second mobile unit is used to map the two-dimensional features while the second mobile unit traverses the surface. Three-dimensional positions of the two-dimensional features mapped by the second mobile unit are determined within the second mobile unit and by using the three-dimensional map.
