Lithologic identification and characterization using ETM+ (Landsat 7). Study case of the Upsala glacier basin, Argentine

Revista oficial de la Asociación Española de Teledetección [EN] The object of this study aims to evaluate and analyze digital image processing techniques applied to the Enhanced Thematic Mapper Plus (ETM+), in order to demark and characterize the outcropping lithologies on the Upsala Glacier basin, Santa Cruz, Argentine Republic. The prolific technological and spatial development experienced in the last decades has given place to the generation, without precedents, of multiple remote sensors capable of capturing information of the terrestrial surface and also the improvement of digital image processing techniques and software; amongst them, the amazing possibilities in the detection and differentiation of diverse covers present on the terrestrial surface can be highlighted, such as glaciers, volcanoes, vegetation, soils, water, types of rock outcrops, etc. This situation improves mapping and monitoring of natural phenomenon in the Earth Sciences field. The proposed methodology includes radiometric corrections, elimination of unwanted covers, statistical evaluation in the combination of the most appropriate bands, application of the Z index, discretization of the statistical series, entailing tasks of spectral classification with field samples and a later validation. Valuable results were obtained by means of digital processing of images, that were validated yielding a 82% of accuracy in the proposed classification, which are good results taking into account the diversity of covers present and the lithological heterogeneity that makes up each pixel (30m). These results were also validated with existing geological maps, obtaining a good agreement. [ES] El objetivo del presente estudio se enfoca en evaluar y analizar técnicas de procesado digital de imágenes aplicadas al sensor Enhanced Thematic Mapper Plus (ETM+), a fin de demarcar y caracterizar las litologías que afloran en la cuenca del glaciar Upsala, Santa Cruz, República Argentina. El prolífico desarrollo tecnológico-espacial experi-mentado en las últimas décadas ha dado lugar a la generación, sin precedentes, de sensores remotos capaces de capturar información de la superficie terrestre y a la mejora de las técnicas de procesado digital de imágenes, entre las que destacan las posibilidades en la detección y diferenciación de diversas cubiertas presentes en la superficie terrestre como glaciares, volcanes, vegetación, suelos, agua, tipos de rocas que afloran, etc. Esta situación ha coad-yuvado y posibi