A method for the determination of a fill level of a cylindrical oil tank with a shell wall and a floating roof , comprising the steps: - Transmission (S1) from an oblique viewpoint of microwaves, from a satellite that is orbiting or stationary in an earth orbit, in the direction of the cylindrical oil tank located on the earth's surface, - Reception (S2) of microwaves reflected from the cylindrical oil tank , and generation of a radar image using a synthetic aperture method, characterised by the steps: - Determination (S3) of a multiplicity of point scatterers from the radar image by means of image processing and/or signal processing, such that the radar image then has only binary information, wherein the point scatterers are produced by reflections of microwaves striking the cylindrical oil tank , and appearing on the radar image as points that stand out in colour, - Generation and adjustment (S4) of at least two semicircles using a method of non-linear optimisation, or a Hough transformation, such that the point scatterers lie on, or as close as possible to, the semicircles, wherein the semicircles have at least the following: a first semicircle assigned to a line of contact between an outer face of the shell wall and the ground, and a second semicircle assigned to a line of contact between an inner face of the shell wall and an upper end face of the floating roof , - Determination (S5) of a diameter of the oil tank , and a height of the floating roof relative to the ground, from the respectively adjusted first semicircle and second semicircle , and - Determination (S6) of the fill level of the oil tank from the diameter of the oil tank and the height of the floating roof determined. - Transmission (S1) from an oblique viewpoint of microwaves, from a satellite that is orbiting or stationary in an earth orbit, in the direction of the cylindrical oil tank located on the earth's surface, - Reception (S2) of microwaves reflected from the cylindrical oil tank , and generation of a radar image using a synthetic aperture method, characterised by the steps: - Determination (S3) of a multiplicity of point scatterers from the radar image by means of image processing and/or signal processing, such that the radar image then has only binary information, wherein the point scatterers are produced by reflections of microwaves striking the cylindrical oil tank , and appearing on the radar image as points that stand out in colour, - Generation and adjustment (S4) of at least two semicircles using a method of non-linear optimisation, or a Hough transformation, such that the point scatterers lie on, or as close as possible to, the semicircles, wherein the semicircles have at least the following: a first semicircle assigned to a line of contact between an outer face of the shell wall and the ground, and a second semicircle assigned to a line of contact between an inner face of the shell wall and an upper end face of the floating roof , - Determination (S5) of a diameter of the oil tank , and a height of the floating roof relative to the ground, from the respectively adjusted first semicircle and second semicircle , and - Determination (S6) of the fill level of the oil tank from the diameter of the oil tank and the height of the floating roof determined. <EOS>