The power of this technique was demonstrated by Snavely et al.(2007) who developed the Bundler software and used it to construct3D models of well-known world sites, such as Notre Dame, based onhundreds of overlapping photographs available from communitywebsites. The SfM technique is based on identifying matching fea-tures in images taken from different viewpoints. Image features areidentified by the scale invariant feature transform (SIFT) algorithm(Lowe, 2004), which is robust in terms of its feature descriptors forimage features at different viewing angles.