Which of the following is NOT a type of contour line?

• A. Index
• B. Esoteric
• C. Intermediate
• D. Supplementary

Answer: (B)

Contour lines on topographic maps come in a few standard types to help interpret elevation. Index contours are the bold, labeled lines that mark elevation and anchor the map’s elevation framework. Between them lie the intermediate contours, which are the regular, lighter lines that fill in the steps of elevation at the map’s contour interval. Supplementary contours are dashed lines added to show extra detail or approximate elevations between the regular intervals, helping to depict terrain more precisely in areas where the slope is gentle or when more nuance is needed. The term esoteric isn’t a recognized contour-line type on standard maps, so it doesn’t fit with how terrain is depicted.