Maps fascinated Leonardo. He owned a number of them and others he borrowed from the Florentine banker Giovanni de' Benci. As an itinerant artist, Leonardo drew maps and landscapes as orientation devices for each new urban or rural environment. His interest in cartography gained momentum between 1496 and 1510, when he worked for patrons who were interested in land management or its acquisition.
Like Petrarch before him, Leonardo wanted to identify the physical landmarks around him and indicate the place names he had read about. Adopting a Ptolemaic approach to recording the terrain, Leonardo checked and rechecked his data to achieve the greatest precision. Several maps of the Arno Valley indicate his continued interest in relaying the correct view. His landscapes and topographical measuring, therefore, became indexible tools for altering the borders or features of the contado of Florence, Imola or Milan. To capture spatial relationships and true proportions, Leonardo invented new methods of recording the land using odometers and a magnetic compass with a movable sight vane. His new methods resulted in the earliest extant ichnographic plan, the Mappa di Imola, which dates to about 1502.
In a plan of Milan, now in the Codex Atlanticus, fol. 199v, he offered another innovation: not only did he draw an ichnographic plan, but he also used it to construct a perspective view (fig. 1). The two resulting views of Milan indicate his conception about the city in which he resided: its general layout and the spatial relationships of its major monuments. First he drew the plan. From it he made a constructed perspective, that is, a 3-point perspective, within an ellipse in order to show in perspective the city and its confining anular canals (fig. 2). This method was new then but it remained in use until the advent of computers. The small cube at the center of the plan marks Leonardo's reference point for the view known as a volo d'uccello, or bird's-eye view. While inserting himself into his surroundings, Leonardo also distances himself from the area, becoming the bird that surveys it. It is no wonder he produced this viewpoint after having studied for many years the flight of birds.
This low aerial viewpoint delineated spatially his novel considerations for urban plans and for the relationships between man and the solids of edifices, the voids of streets and piazzas and the life-giving veins of water coursing through the city. He represented the major monuments in a lighthouse-like way as the beacons that affected daily life. An important view of the urban spaces of Milan, it archives some of the many transformations that took place under Lodovico Sforza and programs the future canal projects for Charles d'Amboise, the French governor of Milan.
In another plan from around the same period he indicates alternative canalization, city gates and major roads (fig. 3). Interestingly, in the accompanying labels sometimes he inverts the names of city gates, thereby always retaining his orientation to the familiar monuments, as if he were walking around the circle.
Throughout his mapmaking process, Leonardo is physically present. He familiarizes himself with an area and determines its frontiers, often on a patron's request. Although the processes of cartography require measurement, proportioning, and the consideration of texture, light and other technical requirements, the efforts also reflect his quest to situate his personal pin on the map. His high aerial topographical views-unusual for their time-place him as a bird-man, observing from an imaginatively powerful, yet incorporeal, vantage point.
In addition, Leonardo's chorographic plans and land sketches allow us to view historical processes as they document changes in borders and identify zones of possible development. They mark the commencement of actual territorial acquisitions, registering the power to control, contain and change the terrain. Through mapmaking Leonardo came to know the land and everything in it, although at times the high artistic level of these functional maps and gorgeous landscapes obscures the artist's obsession to understand the universe. This practice was for Leonardo one path to the acquisition of knowledge via the senses and empirical experimentation, a path that linked critical modes of thought and brought the artist into the incipient realm of early modern science.
Through his eyes Leonardo apprehended the workings of the world. For him, vision acted as the foremost instrument of knowledge. He recorded his surroundings using precise draftsmanship in order to master his environment. His intention was "to consult experience first and then with reasoning show why such experience is bound to operate in such a way" (Manuscript E, fol. 55r). This sense-based approach-more Scholastic and medieval-allowed him to exact knowledge from his lived circumstances and careful observation. The known, once assimilated through drawing, could be quantifiably represented and thus linked vision to the Aristotelian notion of scientia (knowledge). He transformed the unknown and the possible into a visual idea, incorporating the Platonic premise that abstraction generates genuine knowledge. Leonardo then moved drawing easily into the early modern world influenced by Plato, attempting to capture the elusive ideal of nature.
Fig. 1 Leonardo da Vinci. Plan and view of Milan. Codex Atlanticus, folio 199v, Veneranda Biblioteca Ambrosiana, Milan.
Fig. 2 Leonardo da Vinci. Plan and view of Milan. Codex Atlanticus, folio 199v, Veneranda Biblioteca Ambrosiana, Milan (detail).
Fig. 3 Leonardo da Vinci. Plan of Milan, Windsor, RL 19115r. (Royal Collection Trust / © HM Queen Elizabeth II 2012).