  We analyse the effectiveness of edge detection algorithms for the purpose of
automatically extracting coastlines from satellite images. Four algorithms -
Canny, Sobel, Scharr and Prewitt are compared visually and using metrics. With
an average SSIM of 0.8, Canny detected edges that were closest to the reference
edges. However, the algorithm had difficulty distinguishing noisy edges, e.g.
due to development, from coastline edges. In addition, histogram equalization
and Gaussian blur were shown to improve the effectiveness of the edge detection
algorithms by up to 1.5 and 1.6 times respectively.
