Mangrove extent from 2002 CASI data, Kakadu NP, NT

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Link to the data

This data set consists of a shapefile/kml of mangrove extent for the lower reaches of the West Alligator River Kakadu National Park, with this generated from airborne Compact Airborne Spectrographic Imager (CASI) hyperspectral data data acquired in 2011. Information on the details of the attribute fields for the KakaduNP_2002.shp are located in this document in the section titled 'file.attributes'.

Data Licence and Access Rights

Point of contact

Additional references

  • Lucas, R.M., Finlaysson, C.M., Bartolo, R., Rogers, K., Mitchell, A., Woodroffe, C.D., Asbridge, E.F. and Ens, E. (2017). Historical perspectives on the mangroves of Kakadu National Park. Marine and Freshwater Research (in press).
  • Lucas, R.M., Rowlands, A.R., Niemann, O. and Merton, R. (2004). Hyperspectral Sensors: Past, Present and Future. In: Advanced Image Processing Techniques for Remotely Sensed Hyperspectral Data, P.K. Varshney and M.K. Arora (Eds), pp. 11-49.

Spatial and Temporal extents

File names and descriptions

Related products

Abstract or Summary

From hyperspectral Compact Airborne Spectrographic imager (CASI) data acquired over the mouth of the West Alligator River in Kakadu National Park, mangroves were mapped by first applying a fine scale spectral difference segmentation within eCognition to the blue, red and near infrared wavelength regions. A maximum likelihood (ML) algorithm within the environment for visualizing images (ENVI) software was then used to classify all segments using training areas associated with mangroves, but also water, mud- flats, sandflats, and coastal woodlands. These were identified through visual interpretation of the imagery. With reference to the CASI data, all segments were examined individually and methodically to determine whether they should be reallocated to a non-mangrove class (e.g., mudflats) or as mangrove. Open woodlands dominated by Eucalyptus species were also able to visually identified within CASI data, although their discrimination was assisted by only considering areas where the underlying LiDAR DTM exceeded 10 m, with these associated with the tidally inundated sections.

Compact Airborne Spectrographic Imager (CASI) data, West Alligator River, Kakadu NP, NT

Sampling strategy

The original data were only acquired for the West Alligator River mangroves with an IMU. As neither finer spatial resolution airborne nor field data were acquired at the time of the airborne data acquisitions, the accuracies of the classifications could not be easily quantified. However, the refinement through visual interpretation provided a high level of confidence in the maps of mangroves derived from the segmented AP. To indicate the accuracy of the refined classification, segments were randomly chosen and their assignment was assessed visually against interpretations of the original data. Overall accuracies of 97% were obtained for the CASI classifications of mangrove and non-mangrove (e.g., saltmarsh and sediment) for the West Alligator River.