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Cover 239Table 1.Image acquisition details.SensorSpatial resolutionSpectral resolutionPlatformAltitude 2750 ft (840 m)Date 10 a.m. 16 July 1995CASI (Compact Airborne Spectrographic Imager)1 m8 wavebands; 2 blue, 2 green, 2 red, 2 NIR, varying between 8 and20 nm in width. Waveband settings (nanometres): 402´5± 421´8;453´4± 469´2, 531´1± 543´5, 571´9± 584´3, 630´7± 643´2, 666´5± 673´7,736´6± 752´8, 776´3± 785´4Cessna 172N (a single engine, high wing light aircraft with four seats)Downloaded By: [University of Queensland] At: 11:40 13 November 2010near shore zone. The darker blue in the south-west of the image represents thedeeper waters of so-called Shark Alley.The aircraft was locally owned and not speci® cally adapted for aerial surveywork, and so had no observation hatch. We mounted the sensor by ® tting a speciallydesigned door with incorporated mounting brackets and a streamlined cowling.Power for the operation of the sensor was provided by portable batteries, as theelectrical supply of the aircraft was inadequate. An incident light sensor was ® xedFigure 2. Annotated version of ® gure 1, with crosses representing speci® c habitats asdescribed in the text: yellow =seagrass meadows; red= `blow outs’ within the seagrass;blue= Montastrea reef habitat; black= soft corals on bare substrate.
240CoverDownloaded By: [University of Queensland] At: 11:40 13 November 2010Figure 3. Edge of a seagrass `blow-out’ in a T halassia dominated mixed meadow of Thalassiaand Syringodium (see red cross in ® gure 2). Note the exposed sand substrate, and wall(ca 70 cm high) of seagrass rhizomes and trapped sediment at the blow-out edge.Figure 4.Montastrea reef habitat. Colonies are 1± 2 m in diameter at their bases. Photographwas taken close to blue cross in ® gure 2.