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Steep Land

Steep Land was first acknowledged within the Soil Conservation Act 1938 legislation as Protected Lands primarily due to land degradation impacts associated with tree clearing. Early designation of these areas was mapped by hand using topographic basemaps or interpreted from aerial photographs with 3D stereoscopes at various scales. Then acquisition of satellite data enabled all of NSW to be captured, however this was coarse and mapping of steep lands remained disputable over some areas.

In 2020 Department of Customer Services (DCS) released state-wide 5m resolution digital elevation data in the form of aerial lidar and photogrammetric point-cloud. This has been generated from a combination of 1km, 2km and 5km tiles.

Department of Planning, Industry and Environment have utilised the source data from DCS to create the Steep Land product. Data cleansing and quality assessments have been completed.

The Steep Land 5m product has been created to effectively replace the following existing products: Vulnerable Lands - Steep or Highly Erodible (SHE) SRTM18 - Shuttle Radar

How was Steep Land determined?

Using a smoothed digital elevation model of the earth surface, a slope product was created. This was generated using the Horn 3x3 (1981) method which uses the eight pixels around the central cell to calculate the weighted gradient in north-south and east-west directions, and trigonometry to calculate the maximum slope in the aspect direction.

Having determined the slope values, accurate identification of land 18 degrees or greater across NSW was possible. Steep areas are identified by thresholding the slope value. Only the values of interest are extracted.

The Steep Land products are available covering NSW or in zone mosaics 54, 55, 56. They are in binary form. Please adjust the symbology as required.

  • 0 - Not Steep (below 18 degrees
  • 1 - Steep (areas identified as 18 degrees or greater).

Please contact data.broker@environment.nsw.gov.au for more information.

Data and Resources

  • Data Quality StatementPDF

    Data quality statement for Steep Land

  • SteepLand18_zone54ZIP

    Steep Land 18 degrees or greater covering MGA Zone 54 GeoTiff - 10MB

  • SteepLand18_zone55ZIP

    Steep Land 18 degrees or greater covering MGA zone 55 GeoTiff - 110MB

  • SteepLand18_zone56ZIP

    Steep Land 18 degrees or greater covering MGA zone 56 GeoTiff - 180MB

  • SteepLand18_nswZIP

    Steep Land 18 degrees or greater covering NSW GeoTiff - 300MB

  • Fact Sheet - SteepLandPDF

    Background, development and naming information

Metadata Summary What is metadata?

Field Value
Data Type Raster
Metadata Date 28/06/2021
Date Created 24/06/2021
Date Revised 28/06/2021
Date Published 28/06/2021
Edition 1
Purpose Planning, and management information
License Creative Commons Attribution 4.0
Update Frequency Data is updated as deemed necessary
Keywords PHOTOGRAPHY-AND-IMAGERY-Remote-Sensing,LAND-Topography
Spatial

Dataset extent

Geospatial Topic Environment
Language English
Temporal Coverage From 01/01/2011 - 10/12/2019
Datum GDA94 Geographic (Lat\Long)
Landing page https://datasets.seed.nsw.gov.au/dataset/steep
Legal Disclaimer Read
Attribution Department of Planning, Industry and Environment asserts the right to be attributed as author of the original material in the following manner: "© State Government of NSW and Department of Planning, Industry and Environment 2021"