Since its conception over a century ago, photogrammetry has been a mathematically rigorous cartographic tool for extracting geodetic information from stereo photography. Defined by the American Society of Photogrammetry as ‘the science or art of obtaining reliable measurements by means of photography’ (Whitmore, 1952), photogrammetry provides the foundation for many standard cartographic datasets that serve as tools in the volcanologist’s kit, including topographic maps, orthophotographs, digital elevation datasets, geologic maps, and infrastructure maps.
KeywordsGlobal Position System Digital Elevation Model Aerial Photography Lava Dome Stereo Pair
Unable to display preview. Download preview PDF.
- 2.Careful calibration of aerial cameras and lenses is essential to achieving the best possible photogrammetric precision. Clarke and Fryer (1998) provide a thorough discussion of the development of calibration methods and models, which includes the following introduction (p. 58): ‘A camera consists of a image plane and a lens which provides a transformation between object space and image space. This transformation cannot be described perfectly by a perspective transformation because of distortions which occur between points on the object and the location of the images of those points. These distortions can be modelled. However, the model may only be an approximation to the real relationship. How closely the model conforms to reality will depend on the model and how well the model’s parameters can be estimated. Choosing parameters which are both necessary and sufficient has taxed those involved in the process of lens calibration for as long as lenses have been used to make precise measurements! Google Scholar