What is a continuous elevation line called in contour mapping?

In contour mapping, a continuous elevation line is known as a contour line. These lines connect points of equal elevation on a map, allowing for the visualization of terrain relief and the slope of the land. Each contour line represents a specific elevation and helps in understanding the topography of the area being surveyed. The closer the contour lines are to each other, the steeper the terrain is in that area.

Topographic line could be a term used in a broader sense to refer to lines on a topographic map, but it is not the standard term for continuous elevation lines. Elevation marker generally refers to a specific point indicating height above a reference level rather than a continuous line. Datum line refers to a reference point or surface from which elevations are measured but does not represent the continuous nature of elevation changes across a mapped area like contour lines do. Therefore, the term contour line is the most accurate and widely accepted term used to describe a continuous elevation line in contour mapping.