Package org.apache.sis.referencing.datum

package org.apache.sis.referencing.datum
Relationship of a Coordinate­System (an abstract mathematical entity) to the earth or other system. An explanation for this package is provided in the OpenGIS® javadoc. The remaining discussion on this page is specific to the SIS implementation.

The root class in this package is Abstract­Datum. Various subclasses are defined for various kinds of relationship to the Earth or time (geodetic, vertical, temporal), or to platforms (mobile or not) (engineering, image). Some of those SIS subclasses provide additional methods that are not part of OGC/ISO specifications:

Datum shifts

Three classes are provided in support of coordinate transformations between different datums:
  • Bursa­Wolf­Parameters performs an approximation based on a translation, rotation and scale of geocentric coordinates.
  • Time­Dependent­BWP is like Bursa­Wolf­Parameters, but varies with time for taking in account the motion of plate tectonic.
  • Datum­Shift­Grid is used for more accurate transformations than what Bursa­Wolf­Parameters allows, by interpolating the geographic or geocentric translations in a grid (e.g. NADCON or NTv2) instead of apply the same transformation for every points.