GEMSModels: Modernisation of the P223 codes

The P223 suite of electromagnetic modelling codes, developed by CSIRO with industry support through a series of AMIRA projects, has been a trusted foundation for EM modelling since its release in 2008.

Today, many companies still use these tools but their legacy design makes them increasingly difficult to maintain, adapt, and extend to meet evolving project requirements. That can slow down interpretation, increase risk, and complicate integration with modern workflows.

Aegis Geophysics is addressing this with Geophysical Electromagnetic Survey Models (GEMSModels), a next‑generation modelling framework designed from first principles to support modern exploration and resource‑evaluation programmes. GEMSModels is a strategic rewrite designed to deliver better performance, greater flexibility, and long‑term sustainability.

The first component of the modernised suite, lyr.jl, already delivers clear performance gains. Developed in Julia with a focus on structured maintainable code, it runs nearly 50% faster than an equivalent modern Fortran 90 implementation, with lower runtime variability. For your projects, that means quicker turnaround on forward modelling, faster iteration during survey design, and more reliable results for decision‑making.

Aegis Geophysics is developing GEMSModels as part of its consulting offering, specifically to help companies streamline EM modelling, reduce uncertainty, and accelerate exploration workflows.

If you would like to discuss how this capability can support your current or planned projects, please contact Aegis Geophysics.