Vector data models are a subset of geographic information through which data are encoded as a geometric definition of a feature, organized within a framework that relates this geometry to the spatial location, context, and proximal relationship. Vector data models are often contrasted to raster data models, encoded in a regular grid spanning an extent with a fixed cell size. Vector data rely on geometric primitives, such as points, lines (sequences of linked points), and polygons (closed geometric forms), with variations on these and additional cases tailored to specific applications as they have emerged during the development of GIS. With the ability to define the location, placement, and interval of points that describe each feature, the resolution of the data are determined by the precision of placement of vertices from the sampled reality or when encoded in a processed form of the data. Due to their finite shapes, defined by their exact placement (point), the segment or overall length (line, polyline), or their area (polygon) vector data are commonly used to encode discrete, rather than continuous, features, with associated characteristics stored in an accompanying table of values corresponding to each shape feature.