A NEW TOOL FOR OBTAINING CARTOGRAPHIC GEOREFERENCED DATA FROM SINGLE OBLIQUE PHOTOS

Since its invention in the first half of the nineteenth century, photography has assumed a leading role as a means for documenting the real world. With the improvement of technology, photography developed into photogrammetry, enabling the mapping and georeferencing of landscape elements beginning with stereo photographs. With the introduction of aerial photography, terrestrial oblique photography became obsolete for cartographic purposes and was nearly forgotten by most specialists in photogrammetry. This evolution is understandable from a technical point of view, but regrettable from the historical and landscape dynamic perspectives. In fact, although they do not systematically cover all territory, terrestrial photographs date back significantly earlier than aerial photography and are generally rich in landscape-relevant details that are easily interpretable because they coincide with normal human view-points. In recent times, the improvement of computing power and the production of high resolution Digital Elevation Models has made the spatial georeferincing of single oblique pictures (monoplotting) more approachable. To our knowledge, however, no specific user-friendly monoplotting tool has been developed so far. We have therefore developed a new tool specially conceived to georeference ordinary individual photographs and then produce map layers (e.g. georeferenced vector data) by drawing them directly on these pictures. The basic requirements that have to be fed into the system are the digital version of the historical picture, the DEM of the depicted landscape, and the real-world coordinates of a suitable number of control points unambiguously recognizable on the picture. Although not absolutely necessary, the tool naturally performs best if the realworld coordinates of the precise shooting point and of the center of the picture are known as well. In this contribution we will illustrate the present version of the tool and the results of the first study cases we have developed thus far. We will also discuss future developments as well as potential fields of application.