Aspect measures the direction in which a land surface slope faces. The direction is expressed in degrees from north. The aspect products were derived from the Smoothed Digital Elevation Model (DEM-S; ANZCW0703014016), which was derived from the 1 arc-second resolution SRTM data acquired by NASA in February 2000. The calculation of aspect from DEM-S accounted for the varying spacing between grid points in the geographic projection. The aspect data are available at 1 arc-second and 3 arc-second …Show full descriptionAspect measures the direction in which a land surface slope faces. The direction is expressed in degrees from north. The aspect products were derived from the Smoothed Digital Elevation Model (DEM-S; ANZCW0703014016), which was derived from the 1 arc-second resolution SRTM data acquired by NASA in February 2000. The calculation of aspect from DEM-S accounted for the varying spacing between grid points in the geographic projection. The aspect data are available at 1 arc-second and 3 arc-second resolution The 3” resolution version of the aspect product has been masked by the 3” water and ocean mask datasets. The metadata and files (if any) are available to the public.

Aspect measures the direction in which a land surface slope faces. The direction is expressed in degrees from north.

The aspect products were derived from the Smoothed Digital Elevation Model (DEM-S; ANZCW0703014016), which was derived from the 1 arc-second resolution SRTM data acquired by NASA in February 2000. The calculation of aspect from DEM-S accounted for the varying spacing between grid points in the geographic projection.

The aspect data are available at 1 arc-second and 3 arc-second resolution

The 3” resolution version of the aspect product has been masked by the 3” water and ocean mask datasets. Lineage: Source data 1.\t1 arc-second SRTM-derived Smoothed Digital Elevation Model (DEM-S; ANZCW0703014016).\t 2.\t1 arc-second aspect product 3.\t3 arc-second resolution SRTM water body and ocean mask datasets

Aspect calculation Aspect was calculated at 1 arc-0second resolution from DEM-S using the finite difference method (Gallant and Wilson, 2000). The different spacing in the E-W and N-S directions due to the geographic projection of the data was accounted for by using the actual spacing in metres of the grid points calculated from the latitude.

The 3 arc-second resolution version of the aspect product was derived from the 1 arc-second slope and aspect products by reconstructing the x and y components of the surface normal vector, averaging those components, then calculating aspect from the aggregated components.

The aspect calculation was performed on 1° x 1° tiles, with overlaps to ensure correct values at tile edges. The data were masked using the 1" or 3” resolution water and ocean mask datasets.

References Gallant, J.C. and Wilson, J.P. (2000) Primary topographic attributes, chapter 3 in Wilson, J.P. and Gallant, J.C. Terrain Analysis: Principles and Applications, John Wiley and Sons, New York.