Australian Digital Elevation Model Data Products

Though detailed enough to detect significant geological structures (Harrington et al., 1982), this DEM suffered from a number of acknowledged limitations from the point of view of hydrological analysis. Extreme heights were not well represented and the 1/10th degree resolution could only support quite generalized drainage structures. The data were also known to contain a number of errors.

The New DEM of Australia The new 1/40th degree DEM of Australia has been calculated by the elevation specific gridding technique described by Hutchinson (1988, 1989). This technique ensures that the DEM has a connected drainage structure by automatically removing spurious pits or sinks. The DEM also incorporates the stream line network digitized from the 1:2.5 M scale map of Australia (Division of National Mapping, 1984).

A summary of the point elevation and stream line data used is given in Table I. A total of about 580 000 elevation data points were used, of which 400 000 were provided by the Bureau of Mineral Resources. These included the 320 000 elevation points used by Moore and Simpson (1982). The inclusion of the trigonometric data points ensured that most of the principal peaks were incorporated into the DEM.

Additional point and stream line data were digitized from 1:250 000 scale topographic maps to provide more detail and to remove remaining drainage anomalies, particularly in areas with complex terrain. Sink data points were also digitized to prevent drainage clearance of genuine depressions, although the drainage enforcement algorithm is generally sufficiently sensitive to ensure that genuine depressions are not cleared, whether or not they have been identified as such in the data (Hutchinson, 1989).

[Summary provided by the Australian National University.]