Three-date landsat thematic mapper composite in seasonal land-cover change identification in a mid-latitudinal region of diverse climate and land use

Abstract

Land-use and land-cover (LULC) classification accuracy in different seasons is not constant due to seasonal variations in spectral characteristics of different land-cover classes. This study addresses the problem of selecting a suitable season for mapping land-cover and identifying changes between seasons of midlatitude (29 deg 30′ to 31 deg 0′S) region of distinctive summer and winter rainfall, a broad altitudinal range, a temperate to subtropical climate and diverse land uses (e.g., summer and winter crops and nature conservation). Six landsat thematic mapper (TM) images from 2007 to 2009 were used taking three sequential three-date composites for seasonal change detection. January (midsummer) was the most suitable season in providing high spectral separability between most classes. The study demonstrates the means for improving LULC classification accuracy through the selection of optimal season for individual LULC class mapping and also provides a method of combining two or more classifications using referential refinement technique to generate aggregate LULC map of the region.