Applying multi-wavelength, multi-polarimetric and interferometric airborne radar data for geological mapping in densely forested north-western Tasmania

Abstract

Geological mapping within densely forested north-western Tasmania presents problems with access that requires the assistance of remote sensing geophysical technologies. Airborne multi-wavelength, multi-polarimetric and interferometric radar data (NASA’s topographic synthetic aperture radar (TOPSAR)) was applied and compared with geophysical, topographic and vegetation classification information to evaluate its potential to assist in the upgrading of existing published geological mapping. Detailed statistical analysis assessing the accuracy of TOPSAR interferometric imagery showed its reliability with only a small dependence on geological lithological units apparent. The finer 5 m resolution TOPSAR data (C-VV InSAR digital elevation model (DEM)) also reveals information about dykes, lineaments and possible structural trends, not seen in the coarser 30 m resolution shuttle radar topographic mission (SRTM) data. Other sources of DEMs are available, such as LiDAR (light detection and ranging), but at a much higher cost. The longer wavelength P band radar with a horizontal–vertical polarisation (P-HV), also shows improvement over shorter wavelength C and L band radar for mapping lineaments and ground cover related to geological units and/or their geobotanical associations. The use of detailed vegetation classification information is recommended as part of any geological interpretation of such multi-wavelength and multi-polarimetric radar data.