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Extracting irrigation structure networks from pre-Landsat 4 satellite imagery using vegetation indices--THIS ONE DOESN"T EXPORT CORRECTLY
  • +3
  • Cory Coakley,
  • Mandy Munro-Stasiuk,
  • James A. Tyner,
  • Sokvisal Kimsroy,
  • Chhunly Chhay,
  • Stian Rice
Cory Coakley
Department of Geography, Kent State University
Author Profile
Mandy Munro-Stasiuk
Department of Geography, Kent State University
James A. Tyner
Department of Geography, Kent State University
Sokvisal Kimsroy
Department of Geography, Kent State University
Chhunly Chhay
Department of Geography, Kent State University
Stian Rice
Center for Urban Environmental Research and Education, University of Maryland, Baltimore County

Abstract

Often discussed, the spatial extent and scope of the Khmer Rouge irrigation network has not been previously mapped on a national scale. Although low resolution, early Landsat images can identify water features accurately when using vegetation indices. We were successful in locating and identifying both water storage and irrigation canals from the time that the CPK (Communist Party of Kampuchea) regime was in power. We discuss the methods involved in mapping historic irrigation on a national scale, as well as comparing the performance of several vegetation indices at irrigation detection. Of the three indices used, NDVI, CTVI, and TTVI (Normalized Difference, Corrected Transformed, and Thiam’s Transformed Vegetation Indexes, respectively), the CTVI provided the clearest images of water storage and transport. This method for identifying anthropogenic water features proved highly accurate, despite low spatial resolution . In many areas these canals and reservoirs are no longer visible, even with high resolution modern satellites. Most of the structures built at this time experienced some collapse, either during the CPK regime or soon after, however many have been rehabilitated and are still in use, in at least a partial capacity.,