Drawing structure contours for planar geological surfaces

planar features, like sedimentary beds with shallow dips, need to be mapped to their extents or else look for other features that cut into the bed a depicted on a map.
For example, on a map, if a shallow dipping bed is cross cut by a stream channel, the map will describe a "V" in the direction of the dip. Thats only a simple case but complex features have more GIS tricks to apply in to analyze or measure these structures
You can reconstruct the movement angle of dip and distances last moved by using a GIS trick that measures the above by collecting and analyzing point sets on a GIS map made from field or satellite data.

We still have to go out to the field to fully quantitate , since many GIS programs have error bars that are incorrect in resource development.