Habitat Map for Lizard Island reef, Australia derived from a photo-transect survey field data collected in December 2011 and September/October 2012

georeferenced dive and snorkel photo-transect surveys were conducted at different locations surrounding Lizard Island, Australia. For the surveys, a snorkeler or diver swam over the bottom at a depth of 1-2m in the lagoon, One Tree Beach and Research Station areas, and 7m depth in Watson's Bay, while taking photos of the benthos at a set height using a standard digital camera and towing a surface float GPS which was logging its track every five seconds. The camera lens provided a 1.0 m x 1.0 m footprint, at 0.5 m height above the benthos. Horizontal distance between photos was estimated by fin kicks, and corresponded to a surface distance of approximately 2.0 - 4.0 m.
Approximation of coordinates of each benthic photo was done based on the photo timestamp and GPS coordinate time stamp, using GPS Photo Link Software (www.geospatialexperts.com). Coordinates of each photo were interpolated by finding the gps coordinates that were logged at a set time before and after the photo was captured.
Dominant benthic or substrate cover type was assigned to each photo by placing 24 points random over each image using the Coral Point Count excel program (Kohler and Gill, 2006). Each point was then assigned a dominant cover type using a benthic cover type classification scheme containing nine first-level categories - seagrass high (>=70%), seagrass moderate (40-70%), seagrass low (

本研究在澳大利亚蜥蜴岛（Lizard Island）周边的多个点位开展了地理参照式潜水与浮潜样带摄影调查。调查过程中，浮潜者或潜水员分别在潟湖、一树海滩（One Tree Beach）及研究站区域以1-2米水深、在沃森湾（Watson's Bay）以7米水深沿底床巡游，使用标准数码相机以固定高度拍摄底栖生物（benthos），并拖曳每5秒记录一次运动轨迹的水面浮标型全球定位系统（GPS，Global Positioning System）。相机镜头在距底栖生物0.5米高度时，可形成1.0米×1.0米的覆盖范围；照片间的水平间距通过脚蹼踢动次数估算，对应水面距离约为2.0-4.0米。
借助GPS照片关联软件（GPS Photo Link Software，www.geospatialexperts.com），基于照片拍摄时间戳与GPS坐标时间戳，对每张底栖生物照片的坐标进行近似估算。具体通过查找照片拍摄前后预设时间点记录的GPS坐标，对每张照片的坐标进行插值计算。研究人员借助珊瑚点计数Excel程序（Coral Point Count excel program，Kohler与Gill，2006），在每张图像上随机布设24个采样点，为每张照片标注对应的优势底栖生物或底质覆盖类型。随后，研究人员将依据包含9个一级类别的底栖生物覆盖类型分类体系，为每个采样点赋予优势覆盖类型：高盖度海草（≥70%）、中度盖度海草（40%~70%）、低盖度海草（