Contoursteken

Contoursteken, or contour lines, are lines drawn on maps that connect points of equal elevation. They are a fundamental element of topographic mapping, used to convey the three‑dimensional shape of the land on a two‑dimensional surface.

Contour lines illustrate terrain relief by showing how elevation changes across the landscape. Close spacing of lines indicates steep slopes, while widely spaced lines suggest gentler terrain. By tracing the arrangement of lines, readers can identify features such as ridges, valleys, plateaus, and depressions, even when the actual ground is not visible.

In most maps contour lines are produced at a regular elevation difference called the contour interval. Larger intervals generalize the terrain and reduce clutter on small‑scale maps, while smaller intervals reveal more detail on large‑scale maps. Some contour lines are marked as index contours, which are thicker and labeled with their elevation to aid orientation.

Contour lines can be generated from various sources, including direct surveys, aerial photography, or digital elevation models (DEMs) within geographic information systems. In GIS, contouring involves interpolation between known elevation points to create a continuous set of lines with associated elevation attributes. Modern maps may combine contour lines with hillshading, color relief, or transparency to improve readability.

Limitations exist: a line map cannot show every minor variation in terrain, and contour labels can become cluttered in rugged areas. Elevation data quality and map scale also affect accuracy and usefulness. Contoursteken remain a widely used tool for navigation, planning, and landscape analysis by providing a concise representation of terrain form.