IV. Simple Instruments for Measuring both Magnetic Azimuth and Altitude. ALTHOUGH undoubtedly for final observations at any monument a theodolite must be employed, using the sun or a star in order to ...

A wide-azimuth survey covering 5,080 sq km started in the Salina del Istmo basin in Mexico’s Bay of Campeche, which contractor Schlumberger Ltd. said provides the first 3D coverage over this ...