1. A method for measuring the area of polygonal planar surfaces in space, wherein a device ( 1 ) is used comprising: a range finder ( 2 ) mounted on a leg support ( 4 ) by means of a frame ( 15 ) having a central point ( 16 ) and being suitable for allowing a user to orient the range finder toward a material point of a surface, known as the targeted point, of his choice, said range finder being suitable for being able to deliver a signal representing the distance separating the central point from the targeted point, means ( 5 , 6 ) for the angular tracking in space of the direction, known as the viewing direction, passing through the central point and the targeted point, these angular tracking means being suitable for being able to deliver signals representing the orientation of the viewing direction relative to a spatial reference frame centred on the central point, the range finder and the angular tracking means thus being suitable for being able to deliver signals representing the spherical coordinates of the targeted point relative to said spatial reference frame, means ( 82 ) for triggering, at the user's command, the acquisition of the spherical coordinates of the targeted point, which means are capable of triggering the storing of digital data representing the spherical coordinates from the signals delivered by the range finder and the angular tracking means, a digital processing unit ( 9 ), suitable for being able to model polygonal planar surfaces from the acquired spherical coordinates of targeted points, known as measuring points, which allow said polygonal planar surfaces to be determined topologically, the method being wherein, for each polygonal planar surface to be measured ( 13 ; 55 ): a series of measuring points ( 19 - 38 ; 60 - 63 ) is selected allowing said polygonal planar surface to be determined topologically and individually, which series comprises, for each edge of the polygonal surface, at most two points, the projections of which on said surface in a predetermined direction pertain to said edge, said surface is subjected to a modelling process in which the measuring points of the series are plotted by orienting the range finder successively toward each measuring point and by triggering the acquisition of its spherical coordinates, the processing unit being suitable for being able to: produce and store a geometric digital model of the polygonal planar surface by generating a segment or a straight line for each edge of said surface from the acquired spherical coordinates of at most two measuring points, calculate and record a value representing the surface area of the digital model thus produced.