Arc

An arc is a curved line that connects two points and is commonly defined as a portion of a circle's circumference. In geometry, arcs are used to represent curved sections of circles and are fundamental in mathematical and engineering applications. In Geographic Information Systems (GIS), an arc is a vector line feature that can be either straight or curved and is used to represent linear geographic features such as roads, rivers, railways, pipelines, utility networks, and administrative boundaries. An arc consists of a sequence of connected points, called vertices, that determine its shape, direction, and curvature. Each arc can store descriptive attributes such as name, length, road classification, speed limit, or feature ID. In topological GIS models, arcs connect nodes and define polygon boundaries, ensuring accurate spatial relationships between geographic features. They support network analysis, routing, connectivity, and spatial editing while maintaining data integrity. As a fundamental component of vector data, arcs enable precise mapping, efficient spatial analysis, and reliable representation of real-world linear features across a wide range of GIS applications.