The application of object based analysis of high spatial resolution imagery for mapping large coral reef systems in the West Pacific at geomorphic and benthic community spatial scales

Coral reef habitat maps at various spatial scales and extent are needed for monitoring and management purposes in coral reef environments. This paper will demonstrate object based analysis for coral reef habitat mapping at reef type, geomorphic zone and benthic community spatial scales, on single reefs or reef systems in Western Pacific. For the study sites, archived high spatial resolution Quickbird and/or Ikonos imagery were acquired and radiometric and atmospheric corrected. Georeferenced benthic photos along transects were acquired for calibration and validation purposes. Hierarchical mapping from reef, to geomorphic zone, then community scales, was completed using object based segmentation and semi-automated labeling through membership rules using field data for calibration and validation. The resulting hierarchal maps for reef type, geomorphic zone and benthic community, had varying accuracies 60-80% for each spatial scale.