A method of producing lane information for use in a map database is disclosed. In at least one embodiment, the method includes acquiring one or more source images of a road surface and associated position and orientation data, the road having a direction and lane markings parallel to the direction of the road; acquiring road information representative of the direction of said road; transforming the one or more source images to obtain a transformed image in dependence of the road information, wherein each column of pixels of the transformed image corresponds to a surface parallel to the direction of said road; applying a filter with asymmetrical mask on the transformed image to obtain a filtered image; and producing lane information from the filtered image in dependence of the position and orientation data associated with the one or more source images.