Detection of coastal change by geo-informatics means
In: Coastal Research Library. Springer: Cham. ISSN 2211-0577; e-ISSN 2211-0585, more
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| 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. |
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