Dunedin New Zealand

Geographic information systems are an important tool for the field of geocomputing. Akey component of every system is the dataÑspatial data has traditionally been labour-intensive to collect, and hence expensive. This paper establishes a new method ofacquiring spatial data from motion video. The proposed method is based upon theprinciples of photogrammetry, but allows position to be calculated with feature trackingrather than point correspondence. By doing so, it avoids many constraints imposed byprevious solutions. The new method is demonstrated with linear and rotational motion. INTRODUCTIONThe field of geocomputing utilises computer models of the real world. While in somecases there is no spatial correspondence between the computer model and reality, manycases require an accurate representation of the real world. For example, geographicalinformation systems (GIS) commonly require accurate, scaled maps of land. A simpleGIS may incorporate a flat two dimensional map from which the computer could, forexample, measure distance or calculate areas. A more complex version may include atopographic map, which is essentially a layered set of two dimensional maps at fixed