Brief description
The seasonal dynamic reference cover method product compares the current ground cover level of each pixel to a reference pixel based on the historical timeseries and is available for Queensland from 1987 to present. It is created using a modified version of the dynamic reference cover method developed by Bastin et al (2012) . This approach calculates a minimum ground cover image over all years to identify locations of most persistent ground cover in years with the lowest rainfall, then uses a moving window approach to calculate the difference between the window's central pixel and its surrounding reference pixels. The output is a difference image between the cover amount of a pixel's reference pixels and the actual cover at that pixel for the season being analysed. Negative values indicate pixels which have less cover than the reference pixels.The main differences between this method and the original method are that this method uses seasonal fractional ground cover rather than the preceding ground cover index (GCI) and this method excludes cleared areas and certain landforms (undulating slopes), which are considered unsuitable for use as reference pixels.
This product is based upon the JRSRP Fractional Cover 3.0 algorithm.
Notes
Supplemental InformationOutput for this product is in the form of a two band TIFF image. Band 1 - the 'delta GC' image. Band 2 - the reference pixel image. Data are available as cloud optimised GeoTIFF (COG) files. COG files are easier and more efficient for users to access data corresponding to particular areas of interest without the need to download the data first.
Lineage
Landsat surface reflectance data > multiple single-date fractional cover datasets > seasonal composite of fractional cover > seasonal dynamic reference cover imageData Creation
Excluded Areas: A mask of excluded areas not to be used in the development of the reference pixels is created. This mask includes areas that have previously been cleared and also undulating plains. This data is obtained from the SLATS historical clearing data across QLD.
Find Reference Pixels: The 90-95 percentile of minimum ground cover are selected from the long term minimum ground cover statistical product, masked with the excluded areas mask described above.
Create the Delta GC layer: For each pixel this raster equals the difference between the ground cover value and the reference pixel value and is scaled by 100 to avoid negative values (ground cover value - reference pixel value + 100). Values closer to 100 are better performing.
Notes
CreditWe at TERN acknowledge the Traditional Owners and Custodians throughout Australia, New Zealand and all nations. We honour their profound connections to land, water, biodiversity and culture and pay our respects to their Elders past, present and emerging.
This dataset was produced using Landsat data sourced from US Geological Survey.
This product provides a way to compare ground cover across the landscape within a particular season.
Data Quality Assessment Scope
local :
dataset
The input imagery was processed to level L1T by the USGS. Geodetic accuracy of the product depends on the image quality and the accuracy, number, and distribution of the ground control points. <br>
The fractional cover v3 model was compared to samples drawn from 4000 field reference sites.<br>
The imagery has been corrected for height displacement using a 3" digital elevation model (DEM) based on the National Aeronautics and Space Administration (NASA), Shuttle Radar Topography Mission (SRTM). <br>
Created: 2022-10-30
Issued: 2024-09-23
Modified: 2024-09-24
Data time period: 1986-06-01
text: Queensland
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Point-of-truth metadata URL
Bastin, G., Scarth, P., Chewings, V., Sparrow, A., Denham, R., Schmidt, M., O’Reagain, P., Shepherd, R., & Abbott, B. (2012). Separating grazing and rainfall effects at regional scale using remote sensing imagery: A dynamic reference-cover method. Remote Sensing of Environment, 121, 443–457. https://doi.org/10.1016/J.RSE.2012.02.021
doi :
https://doi.org/10.1016/J.RSE.2012.02.021
Flood, N. (2013). Seasonal Composite Landsat TM/ETM+ Images Using the Medoid (a Multi-Dimensional Median). Remote Sensing, 5(12), 6481–6500. https://doi.org/10.3390/rs5126481
doi :
https://doi.org/10.3390/rs5126481
Trevithick, R., Scarth, P., Tindall, D., Denham, R. and Flood, N. (2014). Cover under trees: RP64G Synthesis Report. Department of Science, Information Technology, Innovation and the Arts. Brisbane.
- URI : geonetwork.tern.org.au/geonetwork/srv/eng/catalog.search#/metadata/de2d53ec-1c00-46ac-bd01-d253ab0f2eb2
- global : de2d53ec-1c00-46ac-bd01-d253ab0f2eb2
