Vertex

The vertex in GIS is the single point coordinate of the vector feature used for definition of its geometry. A vertex is the exact point where the geometry starts, stops or changes direction along the line or boundary of a vector feature. Vertices are joined together in order to form a variety of geographic entities like roads, rivers, land parcels, administrative units and other geographic features. The polygon features have the vertices which define its boundary with connected segments enclosing the area. For line features the vertices help to define the shape and geometry of the line. GIS systems use the defined coordinate reference system (CRS) for storing the vertex coordinates and positioning of the feature on the map. The manipulation of vertices in order to modify their properties is the important process in GIS data acquisition. The vertex based editing is used in cartography, surveying, digitizing, cadastral mapping, transportation mapping and spatial database management.