Plate 4

The effect of differing spatial resolution on image quality. The area shown includes a sand beach with some seagrass leaf litter on the strand line with Thalassia dominated seagrass beds immediately offshore (dark areas of fairly uniform texture). On the right of the area is a fringing coral reef with waves visible breaking on the reef crest. In between the fringing reef and the seagrass is calcareous sand (pale) with coral reef patches on it. The images are from a black and white aerial photograph scanned at 2 m resolution, a SPOT Panchromatic image (10 m resolution), and colour composite images derived from SPOT XS (20 m resolution) and Landsat Thematic Mapper (30 m resolution).
Oblique aerial photograph of the reef flat at Moorea, French Polynesia showing major geomorphological zones (see Figure 9.1). Mapping such zones using remote sensing is relatively straightforward due to the shallow water depth (< 3 m) and sharp boundaries.
[Photograph: P. Mumby]