/*
* GeoTools - The Open Source Java GIS Toolkit
* http://geotools.org
*
* (C) 2011, Open Source Geospatial Foundation (OSGeo)
* (C) 2003-2005, Open Geospatial Consortium Inc.
*
* All Rights Reserved. http://www.opengis.org/legal/
*/
package org.opengis.referencing.crs;
import org.opengis.referencing.datum.EngineeringDatum;
import org.opengis.annotation.UML;
import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;
/**
* A contextually local coordinate reference system. It can be divided into two broad categories:
* <p>
* <ul>
* <li>earth-fixed systems applied to engineering activities on or near the surface of the
* earth;</li>
* <li>CRSs on moving platforms such as road vehicles, vessels, aircraft, or spacecraft.</li>
* </ul>
* <p>
* Earth-fixed Engineering CRSs are commonly based on a simple flat-earth approximation of the
* earth's surface, and the effect of earth curvature on feature geometry is ignored: calculations
* on coordinates use simple plane arithmetic without any corrections for earth curvature. The
* application of such Engineering CRSs to relatively small areas and "contextually local" is in
* this case equivalent to "spatially local".
* <p>
* Engineering CRSs used on moving platforms are usually intermediate coordinate reference
* systems that are computationally required to calculate coordinates referenced to
* {@linkplain GeocentricCRS geocentric}, {@linkplain GeographicCRS geographic} or
* {@linkplain ProjectedCRS projected} CRSs. These engineering coordinate reference
* systems are subject to all the motions of the platform with which they are associated.
* In this case "contextually local" means that the associated coordinates are meaningful
* only relative to the moving platform. Earth curvature is usually irrelevant and is therefore
* ignored. In the spatial sense their applicability may extend from the immediate vicinity of
* the platform (e.g. a moving seismic ship) to the entire earth (e.g. in space applications).
* The determining factor is the mathematical model deployed in the positioning calculations.
* Transformation of coordinates from these moving Engineering CRSs to earth-referenced coordinate
* reference systems involves time-dependent coordinate operation parameters.
*
* <TABLE CELLPADDING='6' BORDER='1'>
* <TR BGCOLOR="#EEEEFF"><TH NOWRAP>Used with CS type(s)</TH></TR>
* <TR><TD>
* {@link org.opengis.referencing.cs.AffineCS Affine},
* {@link org.opengis.referencing.cs.CartesianCS Cartesian},
* {@link org.opengis.referencing.cs.EllipsoidalCS Ellipsoidal},
* {@link org.opengis.referencing.cs.SphericalCS Spherical},
* {@link org.opengis.referencing.cs.CylindricalCS Cylindrical},
* {@link org.opengis.referencing.cs.PolarCS Polar},
* {@link org.opengis.referencing.cs.VerticalCS Vertical},
* {@link org.opengis.referencing.cs.LinearCS Linear}
* </TD></TR></TABLE>
*
*
* @source $URL: http://svn.osgeo.org/geotools/trunk/modules/library/opengis/src/main/java/org/opengis/referencing/crs/EngineeringCRS.java $
* @version <A HREF="http://portal.opengeospatial.org/files/?artifact_id=6716">Abstract specification 2.0</A>
* @author Martin Desruisseaux (IRD)
* @since GeoAPI 1.0
*/
@UML(identifier="SC_EngineeringCRS", specification=ISO_19111)
public interface EngineeringCRS extends SingleCRS {
/**
* Returns the datum, which must be an engineering one.
*/
@UML(identifier="usesDatum", obligation=MANDATORY, specification=ISO_19111)
EngineeringDatum getDatum();
}