Seagrass coverage in Cockburn Sound, Western Australia (1999)

Cockburn Sound is a sheltered marine embayment 16 km long 9 km wide, and consists of a deep central basin (17-22 m deep) surrounded by shallow platforms. The shallow platforms vary in width from 50 m to 3 km and are where seagrass meadows are found (see thumbnail). The seagrass mapping area was delineated as shallow platforms to a depth of 10 m and covered an area of approximately 3667 ha.
In 1999, flights to acquire aerial photographs were purpose-flown in late-February to early-March when conditions were optimal. These conditions included maximum seagrass leaf cover; maximum water clarity; minimum haze from the adjacent industrial zone; minimum turbidity from dredging, river outflow or industrial activities; minimum cloud cover; weak prevailing winds; and incident sun angle at 20-30. Colour photography with a yellow lens filter was obtained at two altitudes. High altitude imagery was collected at 10,000 m (scale, 1:55,000) for accurate ortho-rectification. The resulting imagery was used as a rectification base for the low-altitude imagery that was obtained at an altitude of 3,800 m.
This dataset is hosted by the Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, on behalf of a consortium of industries and Western Australian Government Departments for the purposes of the Seamap Australia collaborative project (testing a national marine benthic habitat classification scheme). Data and metadata is from https://metadata.imas.utas.edu.au/geonetwork/srv/eng/metadata.show?uuid=81edfca0-9d59-11dc-a0ca-00188b4c0af8

科克本湾（Cockburn Sound）是一处受庇护的海洋海湾，长16公里、宽9公里，由水深17至22米的中央深盆地与周边浅滩平台组成。浅滩平台宽度介于50米至3公里之间，海草床即分布于此（详见缩略图）。海草制图范围被划定为水深10米以内的浅滩平台，总面积约3667公顷。
1999年，用于获取航空摄影影像的飞行任务于2月末至3月初执行，彼时环境条件达到最佳：海草叶盖度达到峰值、水体透明度最高、邻近工业区的雾霾最少、疏浚、河流径流或工业活动造成的浊度最低、云量最少、主导风力微弱，且太阳入射角度为20至30度。本次航拍采用加装黄色滤光镜的彩色摄影系统，分两个飞行高度采集影像：高空影像于10000米高度采集（比例尺1:55000），用于精准正射校正；所得影像作为低空影像的校正基准，低空影像采集高度为3800米。
本数据集由塔斯马尼亚大学海洋与南极研究所（Institute for Marine and Antarctic Studies, IMAS）代表行业联合体与西澳大利亚州政府部门托管，服务于澳大利亚海图（Seamap Australia）协同项目——该项目旨在测试国家级海洋底栖生境分类方案。数据集与元数据可从以下网址获取：https://metadata.imas.utas.edu.au/geonetwork/srv/eng/metadata.show?uuid=81edfca0-9d59-11dc-a0ca-00188b4c0af8