reunaviiva

Reunaviiva, literally meaning boundary line or edge line in Finnish, is a term used across several disciplines to denote the line that separates two regions, shapes, or surfaces. In mathematics, reunaviiva refers to the boundary of a set: the set of points where every neighborhood intersects both the set and its complement. This boundary divides the interior from the exterior and is a fundamental concept in topology and analysis.

In image processing and computer vision, reunaviivat describe the edges or contours of objects detected in images. Edge-detection algorithms seek to identify regions with significant changes in intensity or color, producing maps of reunaviivat that outline shapes.

In cartography and geographic information systems, reunaviiva denotes boundary lines that separate features such as land and water, parcels of land, administrative regions, or natural formations. These lines are essential for spatial data representation and decision-making.

In design, architecture and typography, reunaviiva can refer to the outer contour or silhouette of a form, or to guidelines that define alignment and spacing in layouts.

The term is common in Finnish technical writing and education, and is used with context-specific meanings while retaining its core sense as a separating line. The plural form is reunaviivat, used when referring to multiple boundary lines.