The OpenGIS Geometry Model 11.4.2.3 Point Class 11.4.2.4 Curve Class 11.4.2.5 LineString Class 2054 A  Point  is a geometry that represents a single location in coordinate space. Point  Examples Point  Properties Curve  Properties LineString  Examples LineString  Properties •Imagine a large-scale map of the world with many cities. A  Point  object could represent each city. •On a city map, a  Point  object could represent a bus stop. •X-coordinate value. •Y-coordinate value. • Point  is defined as a zero-dimensional geometry. •The boundary of a  Point  is the empty set. •A  Curve  has the coordinates of its points. •A  Curve  is defined as a one-dimensional geometry. •A  Curve  is simple if it does not pass through the same point twice, with the exception that a curve can still be simple if the start and end points are the same. •A  Curve  is closed if its start point is equal to its endpoint. •The boundary of a closed  Curve  is empty. •The boundary of a nonclosed  Curve  consists of its two endpoints. •A  Curve  that is simple and closed is a  LinearRing . •On a world map,  LineString  objects could represent rivers. •In a city map,  LineString  objects could represent streets. •A  LineString  has coordinates of segments, defined by each consecutive pair of points. •A  LineString  is a  Line  if it consists of exactly two points. •A  LineString  is a  LinearRing  if it is both closed and simple. A  LineString  is a  Curve  with linear interpolation between points. A  Curve  is a one-dimensional geometry, usually represented by a sequence of points. Particular subclasses of  Curve  define the type of interpolation between points.  Curve  is a noninstantiable class.