Detection of Coastal Change by Geo-Informatics Means
The coastal zone is a special geographic area prone to change induced by a variety of processes and factors. Timely monitoring of coastal evolution is critical to enactment of policies for effective planning and minimization of coastal hazards. This paper
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Detection of Coastal Change by Geo-Informatics Means Jay Gao
Abstract The coastal zone is a special geographic area prone to change induced by a variety of processes and factors. Timely monitoring of coastal evolution is critical to enactment of policies for effective planning and minimization of coastal hazards. This paper comprehensively and critically evaluates the methods that have found applications in monitoring coastal change: photogrammetry, GPS and laser scanning. Coastal changes that have been successfully monitored using these methods range from shoreline determination and change detection, to monitoring of cliff retreat and dune erosion. Although the photogrammetric method is able to supply accurate information, it is subjective and tedious to delimit shoreline on photographs. By comparison, the GPS method is very fast and inexpensive, but constrained by site accessibility. The scanning method is also fast but expensive. It can determine shoreline accurately over large areas. In detecting cliff retreat no method is perfect. The GPS method is inapplicable due to the difficulty in accessing this precarious site. Neither vertical photography nor airborne laser scanning is able to sense cliff face. The difficulty in sensing cliff faces is overcome with terrestrial implementation. Terrestrial laser scanning yields more accurate results than the rigorous close-range photogrammetric method. All three methods are capable of detecting dune erosion. The GPS method is rather slow as many widely dispersed data points must be logged. Laser scanning is very fast but can be expensive. It yields more accurate dune heights than photogrammetry that requires complex post-processing. Given their complementary nature, the combination of these technologies will enable the coastal environment to be monitored at unprecedented accuracy and frequency with ever greatest ease.
J. Gao (*) School of Environment, University of Auckland, Auckland, New Zealand e-mail: [email protected] C.W. Finkl (ed.), Coastal Hazards, Coastal Research Library 6, 403 DOI 10.1007/978-94-007-5234-4_15, # Springer Science+Business Media Dordrecht 2013
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Introduction
A huge population around the world lives within a close proximity to the coast owing to its attractive scenery. However, the coastal zone also happens to be the most vulnerable to change. Hurricanes, waves and tsunamis can all cause dramatic changes to it even within a short period of time. In particular, sandy coasts can be severely eroded easily in a storm. Accurate information on the coastal environment and its change over time is needed for planners in devising strategies for laying the infrastructure and in mitigating coastal hazards. Several methods are available for monitoring the coastal zone. With advances in technology, the classic method of ground survey using a theodolite has been gradually augmented with modern methods based on remote sensing. They range from the conventional photographic method to more advanced laser scanning. These methods are comprehe
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