Mapping ancient vegetation cover of the Amazon floodplain using historical MSS/Landsat images (1975-1981)

This study presents a vegetation map of the Amazon River floodplain between the towns of Parintins (AM) and Almeirim (PA), based on Landsat-MSS scenes from 1975 to 1981. Digital processing involved the transformation of multispectral images into fraction-images of vegetation, soil and dark water (shadow), followed by the application of segmentation and region-classification techniques. The resulting map was organized four classes of land cover types: floodplain forest, non-forest floodplain vegetation, bare soil, and open water. Map accuracy was estimated from two types of ground data 1) sample points describing ground cover classes not subjected to major changes, such as permanent water bodies, and identifying indicators of the 30 year old vegetation type landscape (72 points); 2) interviews with community early residents for memory recovery of information on the vegetation cover existing in the 1970 (44 interviews). Altogether, 116 information points was collected along the study area. These points were used to calculate the Kappa Index for agreement between the four field-verified classes and the automatic classification, with value (0.78) indicates the good quality of the floodplain vegetation cover map. The region had 8650 km super(2) coverage of floodplain forest at the time of image acquisition.Original Abstract: Este estudo apresenta um mapa da cobertura vegetal da planicie de inundacao do Rio Amazonas entre as cidades de Parintins (AM) e Almeirim (PA), com base em imagens Landsat-MSS adquiridas entre 1975 e 1981. O processamento digital dessas imagens envolveu a transformacao para imagens-fracao de vegetacao, solo e agua escura (sombra), seguido da aplicacao de tecnicas de segmentacao e classificacao por regiao. O mapa resultante da classificacao foi organizado em quatro classes de cobertura do solo: floresta de varzea, vegetacao nao-florestal de varzea, solo exposto e agua aberta. A precisao do mapa foi estimada a partir de dois tipos de informacoes coletadas em campo: 1) pontos de descricao: para validacao das classes de cobertura nao sujeitas a grandes alteracoes, como e o caso dos corpos d'agua permanentes, e identificacao de indicadores dos tipos de cobertura original presentes na paisagem na ocasiao da obtencao das imagens (72 pontos); 2) entrevistas com moradores antigos para a recuperacao da memoria sobre a cobertura vegetal existente ha 30 anos (44 questionarios). Ao todo foram coletadas informacoes em 116 pontos distribuidos ao longo da