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Aarhus SPIA - ground based TEM software


Aarhus SPIA is a processing and inversion software for ground based TEM and DC/IP data. The graphical user interface of Aarhus SPIA simplifies the processing and inversion process by the possibility of editing data and models in the graphical user interface. The uncertainty can be changed for each data point, a priori information can be added to the starting model, and inversion models can be interpreted before making new inversions. For the inversion, the robust and fast AarhusInv inversion code is used.

Electromagnetic data can be plotted in different ways, e.g. raw dB/dt, stacked dB/dt and apparent resistivity. Noise and spike filtering are done automatically when importing data. The processed data and inversion models are all saved in the same SPIA database and can be imported directly into Aarhus Workbench for easy visualization of the results.

The SPIA TEM module have several inversion methods for Resistivity but also for Cole-Cole and Maximum Phase Angle (MPA) inversions for TEM data affected by IP effects. Read more on these inversion methods here and here.

Perpetual license options

  • Standard License: license can be unregistered manually within the software. Can be used offline for a limited time.

  • Floating license: license is automatically unregistered when SPIA is closed. Needs internet connection and can not be used offline. Optimal if SPIA is used on several PC's.


Key features​

  • Supports all ground based TEM systems

  • Supports the EPSG coordinate reference system

  • Fully developed processing and inversion tools

  • Click to see sounding position on Open Street Maps

  • Inversion with Cole-Cole or MPA for TEM data with IP effects.

  • Simple model report function with single sided pdf files for each station

  • Support for offset configurations. Possible to move GPS to receiver coil position

  • 1D few-, blocky and smooth inversion with AarhusInv code

  • Export of models and data in pdf, png, csv and acsii file formats.

  • Export results to Aarhus Workbench Essentials for visualization on GIF, profiles, themes, PDF report and advanced 3D viewer.

  • Export processed data to Workbench Essentials for LCI/SCI inversions.

  • Use existing model or load external model as starting model for inversion. 


The Aarhus SPIA TEM module have importers that support data from:


  • Geonics ProTEM47/57


  • Monox GeoScope TerraTEM

  • Zonge TEM instruments

  • ABEM WalkTEM

  • HGG WalkTEM

  • Extended USF format files

  • ESF and Amira file format

Aarhus SPIA Inversion

Aarhus SPIA performs a 1D inversion with the robust and fast AarhusInv inversion code. Aarhus SPIA contains two inversion setups:


  • A simple one-click inversion setup where a few- and a many layered model is generated.

  • An advanced inversion setup where the starting model can be fully configured by deciding the number of layers, setting the thickness and depths of each layer and adding a priori information on each layer’s thickness or resistivity. 
    In th advanced setup, it is also possible to load an external start model from file or from an already existing model in SPIA.


SPIA 3.6
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