Coastal change analysis: a quantitative approach using digital maps, aerial photographs and LiDAR

摘要

This case study has demonstrated the significant benefits of employing digital maps and aerial photography for the assessment of historical coastal change. These data have been integrated with a specially commissioned state-of-the-art digital aerial survey and other baseline survey data using specialist digital remote sensing methods and GIS software. The results of this work emphasise the inaccuracies of broad scale assessments adopted by the SMP, where the errors in data and interpretation are neither quantified nor made explicit. This can lead to misleading projections of coastal change where the patterns and rates of change cannot be relied upon for decision making, particularly for high risk sites. The digital approach provides quantitative data of known accuracy from which analysis of historical coastal change can be carried out with confidence. The analysis has been conducted within a geomorphological framework that recognises a number of key controlling landforms along the coastline. Recognition of landform features is considered fundamental to the understanding of historical and future coastal change. The framework assists the identification of the patterns and variable rates of historical coastal change taking account of the influences of coast protection and other intervention measures. Work is still in progress and it is anticipated that further improvements in accuracy and error assessment will be achieved through the use of the orthophoto models. The analysis of historical coastal change will form a key input to the next stage development of a coastal change projection model.