photogrammetric techniques; most notably the ability to visualize
the Earth's surface and extract topographic data from stereo aerial
photographs (e.g., Birdseye, 1940; Eardley, 1942). With the fundamental
principles of photogrammetry now combined with robust
algorithms from the computer vision community, collections of
overlapping photographs can be automatically processed to rapidly
extract the relative 3D coordinates of millions of surface points
(Lowe, 2004; Snavely et al., 2008a, 2008b, 2006). Therefore, the
only specialized resource required for acquisition of 3D data
through photogrammetric techniques is access to suitable software
which depending on computer skills and requirements, is available
through both commercial and open-source options (Table 1).