Coordinate System Base Class

Programming with JViews Maps > Ellipsoid and Geodetic Datums > Spatial Reference System > Coordinate System Base Class

Coordinate System Base Class

INDEX

The JViews Maps supports spatial reference systems where the reference attributes are coordinates. The abstract class ilog.views.maps.srs.coordsys.IlvCoordinateSystem serves as base class for all the coordinate systems.

An IlvCoordinateSystem is defined by:

A optional name.
An array of IlvUnit defining the units to be used on each axis.
An array of String defining the name of each axis.
The dimension of the coordinates in use in the system are defined by the number of axes.

There are three major classes of coordinate systems useful for mapping software:

Geocentric Coordinate System

Represents coordinates in a three-axes Cartesian system, whose origin is the center of Earth. This coordinate system is mainly used in datum conversion.

Geographic Coordinate System

Represents the coordinates specified by angles on an ellipsoid (longitude and latitude). An optional height above the ellipsoid can be used here. For example, this is the standard longitude and latitude given by GPS.

Projected Coordinate System

Represents the coordinates of the Earth on a 2-D surface. There are as many projected coordinate systems as the number of existing projections. Projecting coordinates on a 2-D surface is mandatory to display data on a map. As the projection process introduces some errors, not all projections are well suited to represent an area on Earth. For more information, see Map Projections.

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