The 9 second DEM derived streams are a a fully connected and directed stream network produced in rastor and vector fomats by Australian National University. This product is the raster format, for the the vector product please refer to the Bureau of Meterology's Geofabric Website (http://www.bom.gov.au/water/geofabric/index.shtml). It is built upon the representation of surface drainage patterns provided by the GEODATA national 9 second Digital Elevation Model (DEM) Version 3 (ANU Fenner School of Environment and Society and Geoscience Australia, 2008).

<p>The GEODATA 9 Second Digital Elevation Model (DEM-9S) Version 3 is a grid of ground level elevation points covering the whole of Australia with a grid spacing of 9 seconds in longitude and latitude (approximately 250 metres) in the GDA94 coordinate system. <p>Version 3 of the DEM-9S was calculated by Version 5.2.2 of the ANUDEM procedure (Hutchinson 2007) from comprehensively revised and augmented national GEODATA-250K topographic source data (AUSLIG 1992, Geoscience Australia 2003, Geoscience Australia 2006) using Version 5.2.2 of the ANUDEM elevation gridding procedure. The source data included revised versions of GEODATA-250K elevation points, streamlines, cliff lines and waterbodies, trigonometric points from the National Geodetic Database and additional elevation and sink point data digitised by the Fenner School from 1:100K source material. Version 5.2.2 of the ANUDEM procedure incorporates major upgrades to the modelling of streamlines, lakes, cliff lines and the coastline. <p>GEODATA 9 Second Flow Direction Grid (D8-9S) has been released for the first time with Version 3. The D8-9S is a corresponding grid describing the principal directions of surface drainage across the whole of Australia. This grid was calculated by the ANUDEM procedure as it derived the DEM-9S. It incorporates the data streamline structure and describes the drainage structure continent-wide. It can be used to delineate streamlines and associated catchment boundaries for the DEM-9S. This is particularly useful in low relief areas where drainage structure is not reliably defined by the DEM-9S elevations alone. <p>The product can be used for applications requiring accurate representation of absolute elevation values. The elevation of source data high points (hills or mountains) is well represented in Version 3. The 1:250,000 source scale of the elevation grid makes the product useful for national, State-wide and regional applications. <p>For more detailed information please refer to the User Guide below. <p>Product Information <p>Coverage: Australia, excluding external territories <p>Currency: 2008 <p>Coordinates: Geographical <p>Datum: Horizontal: GDA94; Vertical: AHD71 <p>Available Formats ESRI ASCII Grid, ESRI Grid, ERDAS Imagine Grid, ASCII XYZ Grid

The 1 second Shuttle Radar Topographic Mission (SRTM) derived smoothed Digital Elevation Model (DEM-S) Version 1.0 is a 1 arc second (~30m) gridded smoothed version of the DEM (ANZCW0703013355). The DEM-S represents ground surface topography, excluding vegetation features, and has been smoothed to reduce noise and improve the representation of surface shape. The dataset was derived from the 1 second Digital Elevation Model Version 1.0 (DSM; ANZCW0703013336) by an adaptive smoothing process that applies more smoothing in flatter areas than hilly areas, and more smoothing in noisier areas than in less noisy areas. This DEM-S supports calculation of local terrain shape attributes such as slope, aspect and curvatures that could not be reliably derived from the unsmoothed DEM because of noise. A full description of the methods is in progress (Gallant et al., in prep) and in the User Guide (Geoscience Australia & CSIRO, 2010).

The 1 second SRTM derived DEM Version 1.0 is a 1 arc second (~30m) gridded digital elevation model (DEM). The DEM represents ground surface topography, and excludes vegetation features. The dataset was derived from the 1 second Digital Surface Model (DSM; ANZCW0703013336) by automatically removing vegetation offsets identified using several vegetation maps and directly from the DSM. This product provides substantial improvements in the quality and consistency of the data relative to the original SRTM data, but is not free from artefacts. Man-made structures such as urban areas and power line towers have not been treated. The removal of vegetation effects has produced satisfactory results over most of the continent and areas with defects are identified in the quality assessment layers distributed with the data and described in the User Guide (Geoscience Australia and CSIRO Land & Water, 2009). A full description of the methods is in progress (Read et al., in prep; Gallant et al., in prep). The grid spacing is 1 second in longitude and latitude (approximately 30 metres). Smoothed and drainage enforced versions are under development, and are expected to be released in 2010.

The Environmental Arttibutes Database is a set of lookup tables supplying attributes describing the natural and anthropogenic characteristics of the stream and catchment environment that was developed by the Australian National University (ANU) in 2011. The data is supplied as part of the supplementary Geofabric products which is associated with the 9 second DEM derived streams and the National Catchment Boundaries based on 250k scale stream network. Please consult the spreadsheet below for details of the attributes and their source data.

The Environmental Attributes Database is a set of lookup tables supplying attributes describing the natural and anthropogenic characteristics of the stream and catchment environment that was developed by the Australian National University (ANU) in 2011 and updated in 2012. The data is supplied as part of the supplementary Geofabric products which is associated with the 9 second DEM derived streams and the National Catchment Boundaries based on 250k scale stream network. Please consult the spreadsheet below for details of the attributes and their source data. Version 1.1.5 corrects an error in the connectivity.lut table where the field ARTFBARIER for a subset of records did not correctly flag the presence of an artificial barrier up or downstream of the stream segment.

<p>Note: Geoscience Australia no longer supports users' external hard drives. The data can either be downloaded from the ELVIS Portal or from the Related links. The 1 second Shuttle Radar Topography Mission (SRTM) Digital Elevation Models Version 1.0 package comprises three surface models: the Digital Elevation Model (DEM), the Smoothed Digital Elevation Model (DEM-S) and the Hydrologically Enforced Digital Elevation Model (DEM-H). The DEMs were derived from the SRTM data acquired by NASA in February 2000 and were publicly released under Creative Commons licensing from November 2011 in ESRI Grid format. <p>DEM represents ground surface topography, with vegetation features removed using an automatic process supported by several vegetation maps. This provides substantial improvements in the quality and consistency of the data relative to the original SRTM data, but is not free from artefacts. Man-made structures such as urban areas and power line towers have not been treated. The removal of vegetation effects has produced satisfactory results over most of the continent and areas with defects identified in supplementary layers distributed with the data, and described in the User Guide. <p>DEM-S represents ground surface topography, excluding vegetation features, and has been smoothed to reduce noise and improve the representation of surface shape. An adaptive smoothing process applied more smoothing in flatter areas than hilly areas, and more smoothing in noisier areas than in less noisy areas. This DEM-S supports calculation of local terrain shape attributes such as slope, aspect and curvature that could not be reliably derived from the unsmoothed 1 second DEM because of noise. <p>DEM-H is a hydrologically enforced version of the smoothed DEM-S. The DEM-H captures flow paths based on SRTM elevations and mapped stream lines, and supports delineation of catchments and related hydrological attributes. The dataset was derived from the 1 second smoothed Digital Elevation Model (DEM-S) by enforcing hydrological connectivity with the ANUDEM software, using selected AusHydro V1.6 (February 2010) 1:250,000 scale watercourse lines and lines derived from DEM-S to define the watercourses. The drainage enforcement has produced a consistent representation of hydrological connectivity with some elevation artefacts resulting from the drainage enforcement. <p>Further information can be found in the supplementary layers supplied with the data and in the User Guide.

The 1 second SRTM derived DEM-H Version 1.0 is a 1 arc second (~30 m) gridded digital elevation model (DEM) that has been hydrologically conditioned and drainage enforced. The DEM-H captures flow paths based on SRTM elevations and mapped stream lines, and supports delineation of catchments and related hydrological attributes. The dataset was derived from the 1 second smoothed Digital Elevation Model (DEM-S; ANZCW0703014016) by enforcing hydrological connectivity with the ANUDEM software, using selected AusHydro V1.6 (February 2010) 1:250,000 scale watercourse lines (ANZCW0503900101) and lines derived from DEM-S to define the watercourses. The drainage enforcement has produced a consistent representation of hydrological connectivity with some elevation artefacts resulting from the drainage enforcement. A full description of the methods is in preparation (Dowling et al., in prep). This product is the last of the Version 1.0 series derived from the 1 second SRTM (DSM, DEM, DEM-S and DEM-H) and provides a DEM suitable for use in hydrological analysis such as catchment definition and flow routing.

The National Catchment Database is a linked set of spatial layers and associated attribute tables describing key elements of the surface water hydrology of the Australian continent at a map scale of about 1:250,000. It is built upon the representation of surface drainage patterns provided by the GEODATA national 9 second Digital Elevation Model (DEM) Version 3 (ANU Fenner School of Environment and Society and Geoscience Australia, 2008). The stream network and catchment boundaries contained within the database form foundation elements of the Bureau of Meteorology's Australian Hydrological Geospatial Fabric (Geofabric), the spatial framework that underpins the Australian Water Resources Information System (AWRIS) (http://www.bom.gov.au/water/geofabric/index.shtml). This database adds additional environmental attributes not available through the AHGF. The National Drainage Basins delineate the entire catchment area of any outlet to the sea or inland sink based on the GEODATA 9 second DEM. Available in raster and vector formats.

The National Catchment Database is a linked set of spatial layers and associated attribute tables describing key elements of the surface water hydrology of the Australian continent at a map scale of about 1:250,000. It is built upon the representation of surface drainage patterns provided by the GEODATA national 9 second Digital Elevation Model (DEM) Version 3 (ANU Fenner School of Environment and Society and Geoscience Australia, 2008). The stream network and catchment boundaries contained within the database form foundation elements of the Bureau of Meteorology's Australian Hydrological Geospatial Fabric (Geofabric), the spatial framework that underpins the Australian Water Resources Information System (AWRIS) (http://www.bom.gov.au/water/geofabric/index.shtml). This database adds additional environmental attributes not available through the AHGF. The database contains Levels 1 (drainage divisions) and 2 (aggregated river basins group) National Catchment Boundaries (NCB) in raster format including NCB Pfafstetter coding. The Vector format is available from the Bureau's Geobraic website.