National landform mapping

The Australian Government has made significant investments in building the national datasets and capability that underpinned the first national assessment of climate change risks to Australia's coasts.

At the commencement of the assessment the available data and tools were not sufficient to underpin a national identification of areas at risk around the coastline. Two key requirements emerged, the need for a national:

Digital Elevation Model

The creation of a national Digital Elevation Model (DEM) was the highest priority task identified for the national risk assessment. DEMs provide a three-dimensional model of the ground surface topography and are critical to assessing risk from inundation in low-lying areas. The Australian Government has invested in a mid-resolution DEM covering the entire coast derived from SPOT High Resolution Stereoscopic Reference3D (SPOT) satellite imagery, which was the best resolution available for the entire coast at the time.

State governments and the Australian Government have also made significant investment in high resolution elevation modelling for key urban centres.

The Australian Government has committed to providing access to the generated DEMs for public good purposes and work is progressing on developing the required infrastructure to deliver online access.

To maximise consistency and utility across the network of DEMs available, a National Elevation Data Framework is also being coordinated by ANZLIC—the Spatial Information Council to:

  • improve the quality of data and derived products, such as DEMs
  • optimise investment in existing and future data collections, and
  • provide access to a wide range of digital elevation data and derived products to those who need them.

National geomorphology map

One of the expected impacts from climate change is increasing coastal erosion due to rising sea levels, although rates and the location of erosion are highly dependent on local factors.

The development of a detailed map of coastal landform types—the coastal geomorphology—was essential to provide an understanding of the potential extent of risk from erosion or other types of instability, such as cliff slumping. The data for the geomorphology mapping was derived from over 200 pre-existing maps and datasets, many compiled at different times, at different scales for different purposes, across different jurisdictions and using different classification systems. The geomorphology mapping represents the first dataset to provide coastal landform information in a consistent format for the entire national coast, and at a level of detail that allows features down to 50 metres or less in size (such as small pocket beaches) to be individually distinguished. This is a major step forward in building national capability.

The National Coastal Geomorphology mapping has been peer reviewed in a national workshop at the University of Tasmania and is available at OzCoasts where it can be queried and interrogated through the web browser.

Further information regarding these datasets and how they were used in the national assessment is available in Chapter 3 Approach to first pass national coastal risk assessment.

Polygonal coastal landform map

The Department of Climate Change and Energy Efficiency has also commissioned Geoscience Australia to develop a coastal landform dataset to map the spatial extent of landform types. The dataset will be different to the smartline mapping as it will be in polygonal, rather than line format.

The smartline mapping was done in a line format to allow different landform attribute fields to be displayed or analysed easily. Because of the essentially linear nature of the coasts a line map is a useful and efficient map format, but there are some applications where polygonal (or topographic) mapping is required. For example, while a coastal geomorphology line map can indicate potentially flood-prone areas (such through the Backshore profile attribute), a contour map or DEM is necessary to map the actual areas likely to be inundated.