It is often useful to know rock properties on a path (i.e., a contour) along which some property of a system or phase is constant (e.g., an adiabat, isochore, or isopleth). Typically the path is defined as a function of pressure and temperature as assumed here, but paths can be defined in terms of any allowed independent variable. The construction of such a path involves three steps:

Compute a phase diagram section for the system with VERTEX. See the seismic velocity tutorial for an example of such a calculation.

From the section, compute a table of the property to be contoured. See the seismic velocity tutorial for an example of such a calculation.

From the table, extract the coordinates of the desired contour using the MatLab script perple_x_extract_o_bat.m or follow the more tedious procedure outlined in the adiabatic crystallization tutorial.

Once the path coordinates have been extracted they can be used as input to WERAMI (mode 4) to extract other properties along the path. Alternatively the path can be used as input for a 1-dimensional calculation with VERTEX.