Define faults and breaklines when gridding your data. Faults act as barriers to the information flow, and data on one side of the fault will not be directly used to calculate grid node values on the other side of the fault. Breaklines include Z values.
When Surfer sees a breakline, it uses the Z value of the breakline in combination with nearby data points to calculate the grid node value. Unlike faults, breaklines are not barriers to information flow and the gridding algorithm can cross the breakline to use a point on the other side to calculate a grid node value. Use breaklines to define streamlines, ridges, and other breaks in slopes.
The gridding methods that support faults are: Inverse Distance to a Power, Minimum Curvature, Nearest Neighbor, and Data Metrics.
The gridding methods that support breaklines are: Inverse Distance to a Power, Kriging, Minimum Curvature, Nearest Neighbor, Radial Basis Function, Moving Average, Data Metrics, and Local Polynomial.
Original contour map without faults or breaklines.
The same data set gridded with two faults
The same data set gridded with two breaklines