Final answer:
Every point from a field does not have to be included on a contour line; contour lines represent points of equal elevation and are drawn at set intervals for readability.
Step-by-step explanation:
Not every point from a field has to be included on a contour line on a map. When creating a topographic map, geologists use contour lines to represent points of equal elevation. If every single point were included, the map would be inundated with lines, making it difficult to read. Instead, contour lines are drawn at specific intervals (contour interval) to depict the shape and elevation change of the land.
For instance, while drafting a coastal topographic map, contour lines are continuous and represent elevational increments dictated by the contour interval, whether it's on a flat surface like a map or a 3D model revealing the terrain's shape. Geological features like cliffs or road cuts may provide a cross-section view, but may not reflect the entire geological history of the area as well as a comprehensive map would.