Numerical cartography is determined by an organized set of information consisting of numerical data (cartographic coordinates) and alphanumeric data (coded attributes), organized in databases.
The realization of the digital cartography of the territory is produced by means of numerical photogrammetric restitution according to the required scale of detail 1: 2.000, 1: 1.000 and 1: 500.
The data constituting the numerical cartography describe the objects that constitute the territory to be detected, as natural or artificial details of the terrain.
The coordinates are obtained directly, in numerical form, from the reconstructed stereoscopic model using a digital, analytical or analogue restorer equipped with an automatic data acquisition and recording system. All memorized points are geometrically defined by three coordinates whose tolerance depends on the scale itself.
Each returned element is identified by an encoding, to each planimetric information the altimetric information is also associated and in order to provide an accurate description of the morphology of the terrain, it also proceeds to return both the quoted points and the contour lines.
The details of the territory, typical of traditional cartography, are then integrated with the data necessary for the preparation of further cartographic products, such as roof and roof maps, volumetric maps with the relative printouts, to arrive at the 3D modelling of the blocks and the preparation of topographical databases.