Degree slope (3'' resolution) derived from 1 second DEM-S version 0.1

Abstract

This dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied.

Slope measures the inclination of the land surface from the horizontal. Degree slope represents this inclination in degrees from the horizontal.

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

The 3 second resolution product was generated from the 1 second degree slope product and masked by the 3'' water and ocean mask datasets.

Dataset History

Lineage:

Source data

1. 1 second percent slope product

2. 1 second SRTM-derived Smoothed Digital Elevation Model (DEM-S; ANZCW0703014016).

3. 3 second resolution SRTM water body and ocean mask datasets

Slope calculation

Percent slope was calculated 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 slope calculation was performed on 1deg x 1deg tiles, with overlaps to ensure correct values at tile edges.

The 3 second resolution version was generated from the 1 second percent slope product. This was done by aggregating the 1second data over a 3 x 3 grid cell window and taking the mean of the nine values that contributed to each 3second output grid cell. The 3'' percent slope data were then masked using the SRTM 3'' ocean and water body datasets.

This is version 0.1 of the 3'' resolution percent slope product. Later versions of this dataset may be produced however they are not expected at this time.

Dataset Citation

CSIRO (2012) Degree slope (3'' resolution) derived from 1 second DEM-S version 0.1. Bioregional Assessment Source Dataset. Viewed 14 June 2018, http://data.bioregionalassessments.gov.au/dataset/cbc5c230-cc87-49bb-a635-aec63e5a9723.