Package org.opengis.geometry.coordinate

Core package needed to investigate coordinate-defined geometry. The following is adapted from OpenGIS® Feature Geometry (Topic 1) specification.

A large number of the geometric types in the ISO 19107 standard are defined parametrically, that is they are represented by functions from a set of parameters (in a parametric space, usually a subset of some Euclidean n-dimensional coordinate space) into a coordinate space of some larger dimension. The first few dimensions (up to 3) representing geographic space, the next possibly time, and any remainder representing whatever the application needs, such as distributed attributes or some other measures. The type of geometry is usually determined by the dimension of the parameter space, which will normally be equal to the topological dimension of the resulting geometry. So a 0- parameter geometric object is a point, 1-parameter geometric object is a curve, a 2-parameter geometric object is a surface, a 3-parameter geometric object is a solid.

An n-dimensional coordinate space consists of all n-long arrays of numbers; each array represents a point in the space. In particular situations, this may be restricted to a subset of such points, called the extent of validity, usually based on a set of constraints on values of the various offsets within the array. Each point is associated to a spatial or spatial-temporal location, but a single location may be the target of multiple coordinate space points. Locations given by such structures are called direct positions.

All locations in a list or array shall use the same coordinate system and shall reference reality in a manner representable by continuous functions from the coordinate tuples (DirectPositions) to reality in such a manner that “nearby” coordinates in the DirectPositions map to “nearby” positions in reality. The ISO 19107 standard does not assume that these functions maintain topological dimension. See for example homogeneous direct position.