# Data Geometry

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 $$x=0$$.

The figures below show the receiver position geometry.

## Transmitter Geometry

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.