Comparison of ASTER thermal data sets in lithological mapping at a volcano-sedimentary basin: a case study from southeastern Iran

The thermal bands of ASTER level 1B (L1B) and ASTER 05 (AST_05) data sets were used to map lithological units of an area situated in the southeastern Iranian volcano-sedimentary complex, Kerman Province. The dominant lithological units exposed at the area include felsic and mafic igneous rocks and carbonate masses. The thermal bands of L1B were atmospherically corrected and converted into emissivity using the Reference Channel, Emissivity Normalization, and Alpha Residual algorithms. The Spectral Angle Mapper (SAM) algorithm was implemented on the calibrated L1B and AST_05 data sets. The reference spectra were derived from the image using a spectral endmember selection procedure including minimum noise fraction (MNF), pixel purity index (PPI), and n-dimensional visualizer. Results were compared to the geological map of the study area to determine the accuracy of lithological mapping. The SAM algorithm showed reliable results for discriminating felsic, intermediate to mafic, carbonate, and quartz-sandstone units. AST_05, Reference Channel, and Emissivity Normalization showed approximately similar results with overall accuracy 83, 80.2 and 79.20, respectively. The Alpha Residual data set is less effective in identification of lithological units, as evidenced by a low overall classification accuracy of 50.5. It is concluded that AST_05, Reference Channel, and Emissivity Normalization data sets are suitable for lithological mapping by ASTER data.