Image processing and GIS for hydrothermal alteration mapping, Baguio district, Philippines

Abstract

A technique to map hydrothermally altered zones that involves processing of Landsat TM images and integration of ground data is tested in the Baguio district of the Philippines. Two band ratio images are input into principal components (PC) analysis to map each alteration mineral into separate PC 'mineral images'. Digitized ground data are used for training pixels for the known alteration zones, urban and water areas. The PC mineral images, a digital elevation model (DEM) of the test area and the training pixels are used in a supervised classification to map hydrothermally altered zones. The known hydrothermally altered zones are clearly mapped in the classified image.