Marklutning

Marklutning, or land slope, is the inclination of the ground surface relative to a horizontal plane. It is commonly expressed as a slope angle in degrees or as a percent grade, where percent slope equals the vertical rise divided by the horizontal run times 100. The slope describes how quickly elevation changes over distance and is a fundamental parameter in geomorphology, hydrology, agriculture and civil planning.

Measuring and mapping marklutning can be done in several ways. Field methods include using a clinometer or hypsometer to measure vertical change along a line. In geographic information systems, marklutning is derived from digital elevation models (DEMs) using mathematical formulas that compute the rate of elevation change for each grid cell. Data sources range from national elevation datasets to high-resolution LiDAR and satellite-derived DEMs. Slope values can be represented per point, line, or raster cell, depending on the analysis needs.

Applications of marklutning are widespread. In land-use planning and construction, slope influences suitability for buildings, roads and drainage. In agriculture, slope affects soil erosion risk, irrigation planning, and crop choice. In hydrology and natural hazard assessment, slope governs runoff patterns, sediment transport and landslide susceptibility. Slope is also a factor in forestry, soil depth distribution and microclimate conditions through aspect.

Classification schemes vary by region and purpose, but common ranges include gentle slopes under about 5%, moderate 5–15%, steep 15–30%, and very steep above 30%. It is important to note that slope interacts with aspect, land cover and geological structure, and measurements are scale-dependent with potential errors in flat or rugged terrains.