isolijnen

ISOlijnen, also known as isolines, are lines on a map that connect points with equal values of a chosen variable. The term derives from the Greek isos meaning equal and the Latin linea meaning line, and it is used in geography, meteorology, and cartography. Common examples include isotherms (equal temperature), isobars (equal atmospheric pressure), isohyets (equal precipitation), and contour lines that indicate elevation.

Construction and interpretation: Data used to generate ISOlijnen come from weather stations, satellites, ocean buoys, and numerical models. When observations are irregular, interpolation creates a continuous field; contour lines are then derived by contouring algorithms such as marching squares. The interval between lines (the contour interval) is chosen to balance readability with detail; lines are typically smooth and rarely cross, and closed loops may appear in features like depressions or basins. In a geographic information system, ISOlijnen visualize gradients and spatial patterns, but they are estimates of underlying values at unsampled locations.

Applications: They are widely used in meteorology to map temperature, pressure, and wind fields; in geology and geomorphology for elevation; in hydrology for rainfall or groundwater levels; and in environmental planning and climate science to summarize spatial data. ISOlijnen help convey spatial structure and trends, supporting analysis and decision-making while acknowledging data density and interpolation limitations.