Guiding Principles & Illustrated Examples
GLOSSARY Aerial photography. Aerial photography is the specialists, CAD allows images to be imported and Amateur or handheld GPS devices are not cor- capturing of images of a site or location from an data added manually or input directly from survey rected by a ground-based station and range in aircraft. It provides an efficient and effective means instruments. Data can be displayed in different accuracy between 5 and 15 meters. of quickly documenting the condition of a large site ways, including 2-D orthographic projections or Ground-penetrating radar. Ground-penetrating or a number of sites. It documents many relevant 3-D isometric, or perspective, views. Information radar (GPR) is a nondestructive technique that uses matters and, if sufficiently detailed, can be a can be divided using multiple layers, or views, electromagnetic waves to investigate the under- substitute for conventional mapping and for which can then be recombined in various ways. ground or internal structures of natural and monitoring purposes. There are two general Database. A database is a collection of various human-made objects. It has been used successfully sources for obtaining aerial photography: archival types of data, including photographic images, in investigating the characteristics of and damage research and commissioning flights. Archival sketches and measurements, condition assess- to walls and masonry structures, such as voids, research is a cost-effective means of acquiring ments, and other pieces of information stored in a detachment, cracks, leaks, and deteriorated mortar images of a site taken for other reasons such as systematic way for security and easy retrieval. joints. GPR has a good level of accuracy and is easy road engineering or national topographic mapping Individual records, or data, are separated into sets, to handle and transport.
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