EXPLORATION OF GLACIER SURFACE FACIES MAPPING TECHNIQUES USING VERY HIGH RESOLUTION WORLDVIEW-2 SATELLITE DATA

Glaciers exhibit a wide range of surface facies that can be analyzed as proxies for mass balance studies. Along with hydrological implications, these are in turn quintessential indicators of climate change. The use of moderate to high-resolution (MHR) data for mapping glacier facies has been performed previously; however, the use of very high-resolution (VHR) data for this purpose has not yet been fully exploited. This study uses WorldView-2 (WV-2) VHR data to classify available glacier surface facies on the Samudra Tapu glacier, located in the Himalayas. Traditional methods of facies classification using conventional multispectral data involve band ratioing and/or supervised classification. This study explores glacier surface facies classification by using the unique bands available in the multispectral range of WV-2 to develop customized spectral index ratios (SIRs) within an object-oriented domain. The results of this object-based classification (OBIA) is then compared with five popular supervised classification algorithms using error matrices to determine classification accuracies. The overall accuracy achieved by the OBIA approach is 97.14% (κ = 0.96) and the highest overall accuracy among the pixel-based classification methods is 74.28% (κ = 0.70). The present results show that the object-based approach is far more accurate than the pixel-based classification techniques. Further studies should test the robustness of the object-oriented domain for classification of glacier surface facies using customized sensor specific as well as transferable indices and the resultant accuracies.