MARE2DEM uses a right-handed coordinate system with the z axis positive
down. x is the model strike direction where conductivity is invariant.

Note

There is no assumption about where \(z=0\) resides in the model or
data spaces, although generally it is recommended to set \(z=0\) to
be sea level. Similarly, transmitters and receivers
can be located at any x position, but generally they should be close
to \(x=0\).

MARE2DEM can model both electric and magnetic dipole sources. Magnetic dipoles are always assumed
to be point dipoles while electric dipoles can be point sources or line sources via the length setting
in the data file. The figures below show how the transmitter orientation angles are defined.

UTM referencing is only used for plotting purposes. MARE2DEM
completely ignores this for the 2D EM calculations.

To help with post-inversion plotting of well logs and SEG-Y seismic
overlays on your 2D inversion models, the data file has a line for
specifying the UTM zone, origin and rotation of the 2D model
coordinates. The 2D strike angle is the geographic angle corresponding to the x
direction of the 2D model, clockwise from north. The example below has a
2D strike of 20º. For more info, see Coordinate Transforms for Getting Data Into MARE2DEM.