TM/Landsat 5 images (TM1-TM5 and TM7 spectral bands) from Altamira PA, Brazil (07.20.1991) modified to 60, 100, 120, 200 and 250 m were utilized to evaluate the influence of the spatial resolution in the identification of Forest, Young secondary succession, Mature secondary succession and Non-forest. Thematic maps were made using the Bhattacharya (supervized) classification procedure, followed by visual interpretation. The area of each category was determined in each thematic map, using the 30 m spatial resolution as a reference. Mapping accuracy was evaluated using the Global accuracy, and the Kappa and Tau coefficients. It was found out that: a) the greatest area differences were observed in those maps derived from the 200 m spatial resolution images; b) those categories that dominated the scene spectrally and spatially, increased their influence as the spatial resolution decreased; c) the thematic maps from images with coarser spatial resolution than 200 m presented a slight confusion in map category identification, and d) the spectral confusion between the mapping categories did not present a linear tendency.
Spatial resolution; land-use mapping
