Unmanned aerial vechicle large scale mapping for coastal erosion assessment
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Date
2017
Authors
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Publisher
Universiti Teknologi Malaysia
Abstract
Most of the time, many countries in tropical region are covered by cloud which obstruct the acquisition of high resolution optical image from satellite. Thus, the application of large scale mapping for coastal erosion assessment is difficult to be carried out. The unmanned aerial vehicle (UAV) can be used for acquisition of high resolution image due to its ability of flying at low altitudes and under cloud cover. This study aims to improve the methodology of data acquisition for assessing eroded coastal area by using UAV system designed for large scale mapping. The objectives of this study are (i) to improve the methodology of data acquisition for large scale coastal erosion assessment using UAV with rapid and low cost, (ii) to assess the accuracy of the digital photogrammetric products obtained with different ground control points (GCP) configurations and flying altitude, and (iii) to identify and assess coastal areas due to erosion based on the large-scale orthophoto produced. Two improved methods were introduced in this study: (i) rapid data acquisition and processing, low cost and accurate mapping using UAV, and (ii) modification of the end point rate (EPR) and linear regression rate (LRR) calculation methods by including two new parameters namely the sea water and wave level to detect coastline changes. The modified EPR and LRR methods in detecting the coastline changes of Crystal Bay, Alai, Melaka and Kampung Seri Pantai, Mersing, Johor were evaluated through statistical model, namely t-test and compared with other studies of similar area for validation and verification. Several configurations of GCP, check points (CP) and flying altitude were used to produce the digital elevation model (DEM) and orthophoto which were then processed photogrammetrically. Subsequently, the coastal erosion assessment was performed and the coastline changes of private properties, buildings and residential areas was identified. The results show that the best GCP configuration to produce coastal erosion mapping scale of 1:14000 is 25 points. Meanwhile, the best flying altitude is 300m with accuracies of ±0.002m, ±0.004m and ±0.389m in Northing, Easting and Height respectively. Furthermore, this study shows that most of the coastline, private properties, buildings and residential areas are affected by the coastal erosion. Based on the modified EPR and LRR calculation methods in determining the coastline changes, it is evident that the coastline change rate is significant. In conclusion, this study shows that the UAV system offers many advantages such as its ability to fly at low altitude, low cost, rapid data acquisition and processing in detecting coastline changes and accurate results
Description
Thesis (PhD. (Geomatics Engineering))
Keywords
Coast changes, Drone aircraft--Industrial applications, Map projection