1. A method for generating scaled terrain information with an unmanned autonomous gardening vehicle, the gardening vehicle comprising a driving unit comprising a set of at least one drive wheel, and a motor connected to the at least one drive wheel for providing movability of the gardening vehicle; a gardening-tool; and a camera for capturing images of a terrain, the camera being positioned and aligned in known manner relative to the gardening vehicle; wherein the method comprises: moving the gardening vehicle in the terrain whilst concurrently generating a set of image data by capturing an image series of terrain sections so that at least two images of the image series cover an amount of identical points in the terrain, wherein the terrain sections are defined by a viewing area of the camera at respective positions of the camera while moving; applying a simultaneous localisation and mapping (SLAM) algorithm to the set of image data and thereby deriving terrain data, the terrain data comprising: a point cloud representing the captured terrain, and position data relating to a relative position of the gardening vehicle in the terrain; and scaling the point cloud by applying an absolute scale information to the terrain data.