Intertidal Extents Model Coastal Cells shapefile

The Intertidal Extents Model (ITEM v1.0) product is a national scale gridded dataset characterising the spatial extents of the exposed intertidal zone, at intervals of the observed tidal range. The current version utilises all Landsat observations (5, 7, and 8) for Australian coastal regions (excluding off-shore Territories) between 1987 and 2015 (inclusive).The Intertidal Extents Model (ITEM v1.0) consists of three datasets derived from the Landsat NBAR data managed in the Australian Geoscience Data Cube (AGDC) for the period 1987 to 2015.The Coastal Cells shapefile (ITEM_CoastalCells.shp) identifies the location and extents of the 221 one degree by one degree AGDC cells used in the product, covering the mainland and Tasmanian coastline of the continent (Figure 1). The shapefile also includes information on the lowest (LOT) and highest (HOT) observed tides for the cell, and hence the observed tidal range (HOT-LOT), based on tidal modelling for the time of acquisition of each of the corresponding Landsat tile observations in the cell.Attributes:AGDC Cell IdentifierLowest Observed Tide (LOT) - The lowest modelled tidal offset based on the acquisition times of all observations in the cell. Relative to Mean Sea Level (MSL) (m) x 1000.Highest Observed Tide (HOT) - The highest modelled tidal offset based on the acquisition times of all observations in the cell. Relative to Mean Sea Level (MSL) (m) x 1000.

潮间带范围模型（Intertidal Extents Model, ITEM v1.0）产品为一套国家级栅格数据集，旨在刻画出露潮间带的空间分布范围，数据采样间隔以观测潮差为基准。当前版本整合了1987年至2015年（含首尾年份）澳大利亚沿海区域（不含海外领地）的全部陆地卫星（Landsat）5、7、8号观测数据。

潮间带范围模型（ITEM v1.0）包含三套衍生数据集，其数据源为澳大利亚地球科学数据立方体（Australian Geoscience Data Cube, AGDC）管理的1987年至2015年时段的Landsat NBAR数据。

沿海格网单元形状文件（ITEM_CoastalCells.shp）用于标识本产品所用的221个1°×1°AGDC格网单元的位置与覆盖范围，覆盖澳大利亚大陆本土及塔斯马尼亚州的海岸线（图1）。该形状文件还包含各格网单元的最低观测潮位（Lowest Observed Tide, LOT）与最高观测潮位（Highest Observed Tide, HOT）信息，进而可计算得到观测潮差（HOT-LOT），相关参数基于对应格网内所有Landsat瓦片观测数据的获取时刻所对应的潮汐模拟结果生成。

属性项如下：
AGDC格网单元标识符
最低观测潮位（LOT）：基于格网内所有观测数据获取时刻计算得到的最低模拟潮位偏移量，以相对于平均海平面（Mean Sea Level, MSL）的数值（单位：米）乘以1000存储。
最高观测潮位（HOT）：基于格网内所有观测数据获取时刻计算得到的最高模拟潮位偏移量，以相对于平均海平面（MSL）的数值（单位：米）乘以1000存储。