What are the three types of contour lines?

The three types of contour lines found on maps are index, intermediate, and supplementary. Index contour lines are the primary reference lines that are usually darker and labeled with an elevation value. They help to indicate the elevation at regular intervals.

Intermediate contour lines fall between the index lines and are used to illustrate less significant elevation changes. These lines are typically lighter and not labeled, and they provide finer detail for understanding the terrain's shape.

Supplementary contour lines are used when there is a steep slope or to enhance clarity in areas where terrain elevation changes rapidly. These lines are typically drawn with a dashed or different style, indicating that they represent less significant elevation changes compared to the index and intermediate lines.

Understanding these different types of contour lines is essential for land navigation and terrain analysis, as they help visualize elevation changes and the physical features of the landscape.