Figure 1.
Study site location (top panels), bathymetry grid with superimposed ground truth observation transects (bottom left panel) and backscatter mosaic (bottom right panel).
Table 1.
Detailed explanations of all layers derived from bathymetry and the backscatter mosaic.
Figure 2.
(a) Backscatter mosaic overlaid with the results of the region-growing segmentation. (b) Detailed view of the mosaic segmentation as indicated by the red box in (a). (c) Examples of four different angular response curves computed from polygons 1–4 as indicated by the blue sections in (b).
Figure 3.
Maps of the angular response features, derived from the backscatter angular response curves between 30° and 50°; (a) mean, (b) least square slope, (c) skewness and (d) kurtosis.
Table 2.
Number of samples used for model development and accuracy assessment, for each biota class.
Table 3.
Variable combinations and classification accuracy results for the different models.
Table 4.
Correlation of determination (R2) using the linear Pearson correlation measure between all variables used in this study.
Figure 4.
Measures of the relative importance of the variables produced from Models 1 and 2.
Bathy = Bathymetry, Comp = Complexity, Asp = Aspect, BPI = Bathymetric Position Index, Slo = Bathymetry slope, Maxc = Maximum curvature, Rug = Rugosity, Mos = Backscatter mosaic, HSIR = Red layer of Hue Saturation and Intensity (HSI), HSIG = Green layer of HSI, HSIB = Blue layer of HSI, Hom = GLCM Homogeneity, Ent = GLCM Entropy, Cor = GLCM Correlation, ARmean = Mean of angular response, ARslo = Slope of angular response, ARsk = Skewness of angular response and ARkur = Kurtosis of angular response.
Figure 5.
Per class accuracy (mean of user and producer's accuracy) for models 1 and 2 (with and without the backscatter angular response features).
MB = Mixed Brown algae, INV = Invertebrates, MRI = Mixed Red algae and Invertebrates, NVB = No Visible Biota, MBI = Mixed Brown algae and Invertebrates, MBMR = Mixed Brown algae and Mixed Red algae, and MGI = Mixed Green algae and Invertebrates.
Figure 6.
Habitat map of biota classes produced from the simplest model of variable combinations (Model 6) overlaid with the hill shaded bathymetry.
Table 5.
Pairwise comparison of error matrices between Model 2 and the four simpler models.