The 2005 coral-bleaching event roatan (Honduras): Use of pseudoinvariant features (PIFs) in satellite assessments

G. P. Rowlands, Sam Purkis, B. M. Riegl

Research output: Contribution to journalArticle

21 Scopus citations


Radiometric normalisation is a necessary precursor to detecting coral-bleaching from a time series of imagery. Using IKONOS and QuickBird, the pseudo-invariant-feature (PIF) approach was assessed, and found that small subsets and landbased PIFs lead to erroneous normalisation. In comparison, favourable results were achieved by using benthic sand and deep water subsets, coupled to a sun-deglint process. Furthermore, it was found the more traditional strategy of ‘difference imaging’ to be compromised by slight spatial alignment errors between image sets. Our alternative approach, based on spectral radiance, ably discerned significant brightening of areas of seafloor populated by dense stands of Acropora, corroborating the occurrence of a documented bleaching event.

Original languageEnglish (US)
Pages (from-to)99-112
Number of pages14
JournalJournal of Spatial Science
Issue number1
StatePublished - Jan 1 2008
Externally publishedYes


ASJC Scopus subject areas

  • Geography, Planning and Development
  • Energy(all)
  • Atmospheric Science

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