Abstract:We have mapped the primary native and exotic vegetation that occurs in the Cerrado-Caatinga transition zone in Central Brazil using MODIS-NDVI time series (product MOD09Q1) data over a two-year period (2011)(2012)(2013). Our methodology consists of the following steps: (a) the development of a three-dimensional cube composed of the NDVI-MODIS time series; (b) the removal of noise; (c) the selection of reference temporal curves and classification using similarity and distance measures; and (d) classification using support vector machines (SVMs). We evaluated different temporal classifications using similarity and distance measures of land use and land cover considering several combinations of attributes. Among the classification using distance and similarity measures, the best result employed the Euclidean distance with the NDVI-MODIS data by considering more than one reference temporal curve per class and adopting six mapping classes. In the majority of tests, the SVM classifications yielded better results than other methods. The best OPEN ACCESSRemote Sens. 2015, 7 12161 result among all the tested methods was obtained using the SVM classifier with a fourth-degree polynomial kernel; an overall accuracy of 80.75% and a Kappa coefficient of 0.76 were obtained. Our results demonstrate the potential of vegetation studies in semiarid ecosystems using time-series data.

Aos professores do curso de Pós-graduação em Geografia Roberto Arnaldo Trancoso Gomes e Renato Fontes Guimarães, que sempre se mostraram presentes e dispostos a colaborar na construção deste trabalho. Agradeço ao Instituto do Meio Ambiente e dos Recursos Hídricos do Distrito Federal-Brasília Ambiental (IBRAM), pela concessão de licença remunerada, ao curso de Pós-Graduação em Geografia e à gestão do Laboratório de Sistemas de Informações Espaciais (LSIE), por terem disponibilizado a estrutura necessária ao processamento dos dados. Aos meus colegas de IBRAM Alisson, Amanda, Ana Gabriela, Daniel, Dilberto, Fernando, José Flávio, Juliana e Tatiane, verdadeiros amigos que garantiram o apoio que tanto precisei para conseguir finalizar esta dissertação.