WSL Monoplotting-Tool - Reconstructing the landscape dynamic using historical pictures

Developed in the first half of the nineteenth century, photograhy soon became a very effective method of documenting landscape features and dynamics. As a result, many large collections of old photographs in public or private archives exist, representing an enormous resource for the study of landscape evolution and land use change. Unfortunately, on account of the difficulties in obtaining quantitative geographical data from single oblique pictures, this resource long remained unexploited by most researchers in historical geography. In fact, reconstructions of landscape history are often based on the analysis of old maps or aerial photographs.

In recent times, the general increase in computing power, the improvements in digital elevation models (DEM), as well as the implementation of user-friendly and versatile releases of the Geographic Information Systems (GIS) have opened new perspectives for a broad use of single terrestrial oblique pictures for photogrammetric purposes. Monophotogrammetry or monoplotting, mono-photogrammetry or monoplotting represents a photogrammetric system where single oblique and unrectified photographd or aerial (nadir) images are related to the digital elevation models (DEM) of the corresponding real world. In practical terms the camera, the picture and the DEM are related to each other so that a line from the camera center and passing through a selected point in the picture plane, will intersect the land surface (DEM) in the corresponding real point.

At the WSL in Bellinzona we started developing a new monoplotting interface with the aim of offering an intuitive platform for georeferencing and orthorectifying ordinary individual photographs in order to produce georeferenced vector data by drawing them directly on the pictures and exchanging them with traditional GIS-Systems. Resulting polygons may be visualized both on terrestrial pictures or orthophotos and maps (Figs. 1 to 4). Similarly, present geographical elements can be projected on historical pictures (Fig. 5).

	Fig. 1: When carefully looking at this picture dating back to the beginning of the 20 century, one can detect several semi-natural channels for the downhill transport of timber (green: interpretation highly reliable, red: interpretation doubtful).
	Fig. 2:  Thanks to the WSL monoplotting tool it is now possible to plot the recognized channels (usually called «óva», «tracióo» «tröcc», «vandüll» o «vestacc» in the local language) on the historical picture on a 1:10’000 map.
	Fig. 3: In the georeferenced historical picture of Loco dated at 1885 we digitalized the bulk of former terraced vineyards …
	Fig. 4 … and reproduced them on the present map.
	Fig. 5: Thanks to the WSL monoplotting tool it is also possible to visualize present geographical elements on a historical picture, so for instance the contour lines of the present DEM on the historical picture of Loco
Contact address Claudio Bozzini claudio.bozzini@wsl.ch