A map that displays the degree of correlation between wells as a vector that points from one well to another, the length of the vector being related to the degree of correlation from a correlogram. These maps are used in automatic correlation of well logs across a field and indicate where formations are continuous or are terminated.

Reference:

Poelchau HS: 鈥淐oherence Mapping - An Automated Approach to Display Goodness-of-Correlation Between Wells in a Field,鈥?Mathematical Geology 19, no. 8 (1987): 833-850.