Obtaining information on burned areas has been studied and improved in the last decades, and the biggest question is the acquisition of consistent and detailed information about the occurrence of burnings in a simple and effective way. In view of this, remote sensing is a very interesting tool because it allows obtaining information in large areas of difficult access. The identification of areas burned by orbital data is directly related to their spectral behavior. The objective of this study was to analyze the performance of spectral indices in the identification of burned area in OLI/Landsat-8 satellite images. The indices for the before and after fire images were calculated using bands of red and near infrared: NDVI, MSAVI, SAVI, and GEMI, and bands of near infrared and short wave infrared: NBR, BAIMmod, and MIRBImod. The difference between pre and post-fire index was also calculated: dNDVI, dMSAVI, dSAVI, dGEMI, dNBR, dBAIMmod, and dMIRBImod. From these indices, six different compositions (RGB) were created and later they were segmented and classified in a non-supervised way and soon after made the extraction of the area of interest. The results of this classification were validated with the reference data obtained through the visual interpretation of the image. The methods had shown a good quality of classification, with a percentage of accuracy ranging from 85.54 to 92.46% and Kappa value of 0.70 to 0.89. The best method was the dNBR, NBRpost-fire, and dMIRBImod indices in the RGB composite.

aumento da temperatura, diminuição das chuvas, empobrecimento do solo, além de aumentar os riscos de doenças respiratórias. O estado do Tocantins possui características favoráveis para o desenvolvimento de atividades econômicas como a agricultura e pecuária, atrelada a essas atividades está à utilização do fogo para o manejo de áreas de pastagens, atividades agrícolas, entres outros, principalmente em propriedades pequenas. A utilização de dados orbitais representa uma eficiente ferramenta na detecção de áreas queimadas, nesse contexto o presente trabalho utilizou imagens do satélite TM/Landsat-5 para quantificação de áreas queimadas no estado do Tocantins no período de 2003 a 2011. A metodologia aplicada consistiu no processamento de imagens de satélite identificando visualmente as cicatrizes de queimadas nas imagens orbitais. Como resultado tem-se os picos de queimadas em 2007 e 2010 com 5.177.770 e 7.225.070 ha respectivamente, posteriormente, comparando esses dados com o número de focos de calor, confirma-se os maiores registros em 2010 seguido do ano de 2007. Palavras-chave: Cerrado. Cicatrizes de queimadas. Dados Orbitais.