Abstract: The present invention concerns a method for remotely surveying the earth's surface. The method comprises the steps of advancing a plurality of electromagnetic scanning devices (3) along a known path at a predetermined height and velocity above the earth's surface, simultaneously scanning a track (4) of predetermined width on the earth's surface with said scanning devices, detecting with the scanning devices electromagnetic radiation received from the earth's crust in the electromagnetic spectrum, each scanning device responding to a different spectral range within the electromagnetic spectrum, and producing a film record (20) from each scanning device corresponding to the intensity of the radiant energy detected by the scanning device within its spectral range.