A contour surface is a three-dimensional representation that illustrates the shape and elevation of a landscape or object. It uses contour lines, which are curves that connect points of equal elevation, to show how the surface varies in height. This technique is commonly used in topographic maps to help visualize terrain features like hills, valleys, and slopes. In addition to geography, contour surfaces are also important in fields like engineering and computer graphics. They help in modeling complex shapes and understanding spatial relationships, making it easier to analyze and design structures or visual representations in various applications.