Terrain derivatives Derived from the 1 second resolution SRTM DEM-S and DEM-H SUSTAINABLE...
Transcript of Terrain derivatives Derived from the 1 second resolution SRTM DEM-S and DEM-H SUSTAINABLE...
Terrain derivativesDerived from the 1 second resolution SRTM DEM-S and DEM-H
SUSTAINABLE AGRICULTURE FLAGSHIP
John Gallant and Jenet Austin | Terrain Analysis Team, CSIRO Land and Water7th November 2012
Data Source
• Terrain derivatives all based on the national SRTM-derived 1 second DEM-S or DEM-H• Australia wide coverage• Consistency
• Users working from the same version• Accuracy
• Best practice methods• DEM geometry properly addressed
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Available Datasets
• Aspect• MrVBF• Plan and profile curvature• Slope (percent and degrees)• Median slope over 300 m radius circle• Relief (elevation range) over 300 m and 1000 m radius circle• Slope-relief classification• Topographic position index• Contributing area• Topographic wetness index• Cell area (varies with latitude due to geographic projection)
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Location of example datasets
• North-central Tasmania• Some flat areas and some hilly
areas for contrast
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Slope(%)
Relief(300 m radius)
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Slope-reliefClass
TopographicPosition Index
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MrVBF TopographicWetness Index
Resolutions and Coordinate System
• Terrain derivatives are available at two resolutions• 1 second – approximately 30 m• 3 second – approximately 90 m• The 3 second versions have been aggregated from the 1 second versions
using methods that suit the characteristics of each dataset• Geographic coordinate system
• Datum WGS84• Derivatives can be projected to other coordinate systems at a
comparable cell size• 9 second resolution versions do not currently exist
• Not suitable for some derivatives (e.g. TWI, aspect)• If genuinely required, contact John Gallant to discuss an appropriate method
of aggregation
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Data Format
• Terrain derivatives are in ESRI grid format• 1 second resolution datasets are available only as 1x1 degree tiles• 3 second datasets are available as 1x1 degree tiles and as an
Australia-wide mosaic in an ESRI file geodatabase
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Data Access Portal
• Terrain derivatives will be available via the Data Access Portal• https://data.csiro.au/dap• 3 second resolution mosaic• Some metadata publicly viewable now• Public download of large datasets in next release of DAP (early November)• Currently waiting on confirmation of CC-BY licence before all terrain
derivative datasets will be approved and available through the DAP• Link from the TERN Data Discovery Portal
• http://portal.tern.org.au• Soil and Landscape Facility• 1 second resolution datasets – size constraints
• Available within CSIRO• Most have been distributed to a number of agencies via external hard drive
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Future Datasets
• Solar radiation surfaces• SRAD model, accounts for
topography and climate• 1 second resolution• Monthly averages• Testing complete for Tasmania• Estimated completion date for
Australia – March 2013• Prescott Index
• Requires radiation surfaces as input
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January
July
CSIRO Land and WaterDavid JacquierIn charge of toilet paper and other consumablest +61 2 6246 5916e [email protected] www.csiro.au/people/david.jacquier
CSIRO Land and WaterJohn GallantTerrain Analysis Team Leadert +61 2 6246 5734e [email protected] www.csiro.au/people/John.Gallant
CSIRO Land and WaterJenet AustinSpatial Analystt +61 2 6246 5707e [email protected] www.csiro.au/science/Soil-and-
Landscape-Science
SUSTAINABLE AGRICULTURE FLAGSHIP