Abstract: An earth drilling device having a rotary drive and a drilling head connected to the rotary drive via a shaft is disclosed. The shaft runs at least partially axially along a pipe with two pipe ends, the first pipe end of which is connectable to a vacuum source and the second pipe end of which is provided with a pipe opening over which the drilling head at least partially projects. The drilling head is provided with at least two fillet sections connected to the shaft, which are attached to the shaft in radial extension and in projection along the axis of the pipe only partly cover the pipe opening. The fillet sections are each connected to an axially oriented surface section, which contacts the inner wall of the pipe in a gliding manner or contacts an inner wall of a sleeve coaxially connected to the second pipe end when the drilling head rotates. The axially oriented surface sections are each connected to a limb which axially projects over the pipe or the sleeve.

Abstract: The present invention is directed to a method for acquiring elevation data for an area. The method includes using a GPS receiver to map ground elevations while driving back and forth over an area and periodically recording position, elevation, and time. Then, at least one track is made across the parallel tracks so that the cross track intersects the parallel tracks. The data obtained is processed and elevation data from the cross track is used to adjust elevation data for the parallel tracks, compensating for elevation drift in measurements recorded by the GPS receiver. The adjusted data for the entire area is processed using the method of the present invention to obtain an elevation map for the area.