A New Monoplotting Tool to Extract Georeferenced Vector Data and Orthorectified Raster Data from Oblique Non-Metric Photographs

Abstract

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. 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. In this paper, we focus on a new monoplotting tool developed by our research group and we illustrate the basic concept, the solutions implemented and options as well as the results of a case study on land-use and vegetation evolution over a 100-year period. The tool has been conceived to georeference ordinary individual photographs in order to orthorectify the visible landscape or to produce and export map layers (e.g. georeferenced vector data) by drawing them directly on these pictures. The basic requirements of the system are the digital version of the historical picture, the DEM of the depicted landscape, the real-world coordinates of a suitable number of control points unambiguously recognizable on the picture, and – suitable but not mandatory – the real-world coordinates of the precise shooting point and of the centre of the picture.