The city according to the military topographers of Savoy.

By the end of the eighteenth century the city of Turin is the practice field for the cadets of the Theoretical and practical schools of artillery and fortifications, now recognised as a centre of excellence for research and technical-scientific teaching. On the tree-lined avenues of the Valentino future topography engineers will draw lines with the “bojine” and will measure horizontal and diagonal distances; on the batterment between Porta Nuova and the citadel they will practise the use of the square and the measuring of angles, they will start to measure some flat figures on the ground, they will copy the fronts of the fortification with their external works and those "objects" oriented towards S. Salvatore and the river Po. Finally, between Porta di Po and Porta Palazzo they will perform the simplest operations relating to the Praetorian drawing board and execute the designs of the "forts" existing on the town hill. The above text is described in: Progetto delle operazioni da farsi cogli stromenti/ della Geometria pratica in Campagna (Project of the operations to perform with the instruments of practical geometry in the countryside - ASTo, Camerale, Segreteria di Guerra, Carte d’Artiglieria, reg. XXIV, ff. 146-149) drafted in Turin, May 21, 1797, by Luigi Gianotti: successor to the famous "painter of battles" Giuseppe Pietro Bagetti chair of the topographical drawing at the Royal Schools. In the margin of the programme are the notes of the Director, Gerolamo Francesco Zino, who recommended to extend the exercise with the Praetorian drawing board at the survey of the rolling hills. The Director’s comments prove what is now of paramount importance to know about conducting a geometric survey even in those areas not easily accessible. In the Savoy States, the tools and methods for modern topography are scientifically codified in the Theoretical and practical schools of artillery and fortifications (April 16th, 1739 to July 1, 1799) and in the Royal office of topography (April 21, 1738 to 1799 approx.); established under the executive body of the Savoy army: the Azienda d’artiglieria fabbriche e fortificazioni. It is, in fact, within these institutions, through training manuals and practice, where the specialisation in topography of military engineers is accomplished. The context in which one places the process of affirmation of military topography takes into account the fact that in the eighteenth century logistics comes to the forefront as a decisive factor in conflicts. Especially with the wars of succession, the role of communications and procurement becomes vital. The growing size of the armies makes the graphic description of the territory essential, without which the planning of a march, a siege or a camp is impossible. Therefore, the military engineers, until now mainly responsible for the fortifications, must extend their skills to the representation of the territory. In times of war they are called upon to draw up plans of sieges and battles and to conduct the military land surveys taking note not only of the works of defence, but also of their surroundings as related to the scheduling of war actions: the military topographer it is required to be able to represent possible geographies for still invisible armies. Fundamental tools of knowledge of the territory and its resources are the written reports or memoirs (ASTo, Archivio Topografico Segreto, Relazioni, memorie, descrizioni topografiche manoscritte); these are necessary for the scheduling of not only military but also economic and political strategies of the State. In the memoirs those man-made features that can not be represented graphically on paper are also described, for example: the conditions of roads and settlements, the demographic situation, the economic and also moral resources of the populations, on which the possibility of housing and supply of an army largely depend. From the second half of the eighteenth century in the Savoy Schools the operational methods of the topographical survey and graphics techniques receive a broader systemization at the level of treaties. The fundamental turning point occurs with the editing (1756-1775) by Papacino d’Antoni of the six books Dell'Architettura Militare per le Regie Scuole di Artiglieria, e Fortificazione (On the military architecture for the Royal schools of artillery, and fortifications). In particular, relating to the topography of the first book (Della Fortificazione Regolare... 1756, BRT, Militari 288) and the second book (Dell'Attacco, e Difesa delle Piazze Regolari..., BRT, Militari 288), respectively by Carlo Andrea Rana (teacher of mathematics) and Andrea Ignazio Bozzolino (from 1769 director of the theoretical School), are crucial because they determine two new topics: the colouring of the design with its graphic symbolism, and the topographic survey of a site around a fortification. Bozzolino provides a description, "easy and practical", on how to handily proceed in the general surveying of the "country" around a fortress: the engineer will perform the lap of the "piazza" (fort) taking care to note what he finds on the extensions of the alignments of a "face" of a bastion; he should mark, orography and the nature of the land, roads, homes and chapels and especially those sites that can be used for housing cavalry or infantry. In the part devoted to the Disegno in picciolo Rana offers a systematic description of rules, colours and cartographic signs to be adopted for maps that “in addition to the fortification should contain prominent things in the surroundings of the same”. Among the "prominent things" are certainly the populated centres and the religious architecture. The "conspicuous places" surrounded by walls are represented by drawing the plan of their homes; those without walls, on the other hand, are to be reported in the same way as "places not substantial" but with a parish, or rather drawing a small tower placed above a circle coloured in red indicating the centre of the village, the circle must be accompanied by the design of some houses in proportion to the number of existing homes. The roofs of the houses and towers are dark red and black in the shaded part. The chapels are drawn like a single house with a small cross on the front or else, they are represented on the map by a rectangle, coloured all in red, with a black cross. From this textbook the effort is initiated towards the technical definition of a uniform graphical code, which will come to typify the Piemontese military cartography