This topic lists sources of evidence that can be used to supplement the best contouring interpretation. Explains how different interpretations can be obtained from the same data, and how to decide which interpretations are more accurate. Details the key features needed for a pick to represent a geologically meaningful surface. Describes the SEG 1975 seismic polarity convention. Defines several options for picking migrated and unmigrated sections. Lists the recommended practices for choosing map contour intervals. Details the ethics of contouring. Explains the differences between the gridding and triangular approach for machine contouring. Provides the major uses of an interval map and explains how these are made. Describes the contouring differences between two-dimensional high-pass and low-pass filtering.