A single software for processing, inversion, and presentation of AEM data of different systems: the Aarhus Workbench

Abstract

Since 2000 the Aarhus Workbench (aarhusgeo, 2008) is constantly developed to meet the research needs of the HydroGeophysics Group (HGG) at the University of Aarhus. It allows you to handle, process, invert and visualize electric and electromagnetic (EM) data on a common GIS platform. Geological data can be shown on the GIS map and on cross-sections for comparison with the geophysical results. The basic idea of the Aarhus Workbench was to develop a single and integrated software platform for handling a number of different data types. The Workbench uses an open-source client server database to manage data and settings. The benefits of using a databases compared to flat ASCII column files should not be underestimated. Firstly, user-handled input/output is nearly eliminated, thus minimizing the chance of human errors. Secondly, data are stored in a well described and documented format which is well suited for both exchange and storage of data. The Workbench allows the user to present the output of inversions as point themes or as color contoured thematic maps, such as mean resistivity slices, depth to a conductor etc. Models can also be shown on sections which are linked both to the GIS and to displays of data and forward data. The sections can contain numerous layers representing different data types. Over the years HGG has developed stable processing and inversion algorithms for airborne and ground-based EM data. The inversion is known as Laterally Constrained inversion (LCI) for quasi 2-D modeling and Spatial Constrained inversion (SCI) for quasi 3-D inversion. The Workbench implements a user friendly interface to these algorithms enabling non-geophysicists to carry out inversion of complicated airborne data sets without having in-depth knowledge about how the algorithm actually works. Just as important is an extensive system for evaluation of inversion results with plots of results like resistivity models, flight height, pitch, roll, residuals etc.