Australian Coastal Sediment Compartments - Realms

Abstract This dataset provides a hierarchical spatial classification relevant to the assessment of sediment movement in the Australian coastal zone and represents a tool to assist in coastal planning and management. The dataset was the output of the Australian Coastal Sediment Compartments Project undertaken by Geoscience Australia with the aim of generating and delivering a series of discrete spatial units (compartments) in the Australian coastal zone at several spatial scales. The compartments are intended to provide a framework for integrating data and information relevant to sediment movement systems in the Australian coastal zone, and the geomorphic processes that drive them. The data and information provide a fundamental baseline necessary for benchmarking predictions of shoreline response to sea-level rise and other met-ocean processes under varying climate scenarios. In turn, such information is therefore critical to the development of fit-for-purpose adaptation planning and management instruments. By contributing to a robust, nationally consistent, process-based coastal classification, outputs of this project provide a conceptual framework to support coastal management at a range of scales and guide the selection of approaches for modelling shoreline response. The compartments datasets have been generated through the combined experience of an expert panel of coastal scientists. The compartment boundary points along the coastline are typically defined by prominent geological or geomorphic features and were identified by the expert panel as being potentially significant for sediment movement processes in the coastal zone. The attributes contained in these datasets relate to the boundary points only and thus the compartments themselves do not have any data or information attributed to them. The compartments provide a framework within which consideration can be given to the implications of coastal engineering works and other management and planning decisions (Thom, 2014). Currency Date Modified: 06 May 2019 Modification Frequency: As needed Data Extent Coordinate Reference: Geocentric Datum of Australia (GDA94) Spatial Extent North: -9° South: -45° East: 155° West: 111° Source Information eCAT record: [https://pid.geoscience.gov.au/service/ga/90088] Geodatabase download: [https://pid.geoscience.gov.au/dataset/ga/87838] Further information: [https://pid.geoscience.gov.au/dataset/ga/84574] A. McPherson, M. Hazelwood, D. Moore, K. Owen, S. Nichol and F. Howard. 2015. The Australian Coastal Sediment Compartments Project: Methodology and Product Development. Record 2015/25. [https://d28rz98at9flks.cloudfront.net/84574/Rec2015_025_v2.pdf] Thom, B. (2014). Coastal Compartments Project: Summary for Policy Makers. Department of Environment. 5 pp. [http://www.environment.gov.au/system/files/resources/4f288459-423f-43bb8c20-87f91adc3e8e/files/coastal-compartments-project.pdf] Lineage Statement The user is referred in the first instance to Geoscience Australia Record 2015/025 (The Australian Coastal Sediment Compartments Project: Methodology and Product Development; [https://d28rz98at9flks.cloudfront.net/84574/Rec2015_025_v2.pdf]) for further information. The method used to create the polygon extents for the Realms, Regions and Divisions is not recorded but a review of the products suggests that they have not been derived from a digital elevation model or from buffering the coastline. It is believed the extents were digitised on-screen by hand with no further review of the extents, e.g. not clipped back to within Australia's Exclusive Economic Zone (EEZ). In developing the Primary and Secondary Compartment (polygon) datasets, the input datasets and basic process are presented below. Input datasets: * The Australian Bathymetry and Topography Grid 2009 (used to define onshore and offshore bathymetric/elevation limits) * Primary and Secondary boundary points defining compartment limits on (or near) the coastline * Break lines connecting the landward to seaward extent via the Primary and Secondary compartment boundary points * Manually digitised on-screen through visual interpretation of the Australian Bathymetry and Topography Grid and SPOT/Landsat optical imagery to define onshore topographic barriers to sediment movement (e.g. ridges) * Australia's Exclusive Economic Zone (EEZ). Process steps undertaken within ESRI ArcGIS 10.2 suite to create the Primary and Secondary compartments included: * Create the bathymetric/elevation contours (+50 m, +25 m, -50 m and -130 m) from the Australian Bathymetry and Topography Grid * Select smaller features via attribute query and visually verify features are not significant before deleting * Convert the contour lines to polygons * Clip the polygons with the EEZ polygon to ensure the compartment envelopes do not exceed Australia's EEZ * Extract (using the "Erase" tool) the polygon between the inland and offshore limits for each of the Primary (+50 m to -130 m) and the Secondary (+25 m to -50 m) polygons * Create the compartments by applying the "Split Polygons" tool within an edit session with inputs of the compartment envelopes and the break lines * Manually attribute compartments with a sequential number starting at the tip of Cape York and travelling in a clockwise direction * Via a Python script, attribute the Primary and Secondary polygons with a unique identification number composed of State (alpha), parent compartment (numeric) and a sequential number representing the order of occurrence of the primary compartment within the parent compartment e.g. QLD0101, QLD0102. The parent compartments are Coastal Divisions for the Primary compartments and Primary Compartments for the Secondary Compartments Data Dictionary ───────────────────┬───────────────────────────────────── Attribute name │Description ───────────────────┼───────────────────────────────────── ID_Realms │Unique ID given to the coastal realms ───────────────────┼───────────────────────────────────── Description │Description of the coastal realms ───────────────────┼───────────────────────────────────── st_area(shape) │Area of the polygon ───────────────────┼───────────────────────────────────── st_perimeter(shape)│Length of polygon outline ───────────────────┴───────────────────────────────────── Contact Oceans, Reefs, Coasts and the Antarctic (ORCA), Geoscience Australia. [clientservices@ga.gov.au]