Using ALSM to Map Sinkholes in the Urbanized Covered Karst of Pinellas County, Florida 1, Methodological Considerations

Larry D. Searle, Lee J. Florea, H. Len Vacher, Robert Brinkmann

Research output: Contribution to journalArticlepeer-review

Abstract

Comparison of a database of interpreted sinkholes made using airborne laser swath mapping (ALSM) with databases of sinkholes made from interpretation of aerial photographs reveals substantial disagreement. The discrepancies involve the location, number, areas, and circularity of interpreted sinkholes. Methodological factors that contribute to the discrepancies include blockage of ALSM laser returns in thick vegetation, multi-path reflections, and misrepresentation of the true extent of sinkholes. Comparison of two ALSM-derived databases made (1) independently from versus (2) in combination with earlier air photo analysis in undeveloped regions had the following result: one-fourth of the sinkholes interpreted by using the composite method were missed by the independent analysis, and one-third of the sinkholes that were interpreted from the independent analysis were not interpreted as sinkholes using the composite method. Subjective interpretation leads to a high level of uncertainty such that the results of the remote sensing studies are suspect, if not invalid.

Original languageAmerican English
JournalEnvironmental Geology
Volume54
DOIs
StatePublished - May 1 2008

Keywords

  • ALSM
  • Covered karst
  • Remote sensing
  • Sinkholes
  • Pinellas County

Disciplines

  • Earth Sciences
  • Geology
  • Physical Sciences and Mathematics

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