Korkeuskäyriä

Korkeuskäyriä, known in English as contour lines, are lines on a map drawn to connect points of equal elevation above a given level, usually mean sea level. They are a fundamental tool in cartography and topography, providing crucial information about the shape and steepness of the land.

The closer the contour lines are to each other on a map, the steeper the slope of the terrain. Conversely, widely spaced contour lines indicate a gentler gradient. Contour lines never cross or merge, except in the rare case of an overhang or cliff, where they may appear to coincide.

Contour lines are typically drawn at regular intervals, known as the contour interval. This interval is determined by the scale of the map and the nature of the terrain. For example, in mountainous regions, a larger contour interval might be used, while in flatter areas, a smaller interval provides more detail. Index contours are often thickened and labeled with their elevation to make reading the map easier.

The information provided by korkeuskäyriä is vital for various applications, including hiking, surveying, urban planning, and geological studies. They allow users to visualize the three-dimensional landscape on a two-dimensional surface, aiding in route planning, understanding drainage patterns, and identifying features like hills, valleys, and ridges.