org.opengis.metadata.quality.package-info Maven / Gradle / Ivy
Show all versions of geoapi Show documentation
/*
* GeoAPI - Java interfaces for OGC/ISO standards
* http://www.geoapi.org
*
* Copyright (C) 2004-2011 Open Geospatial Consortium, Inc.
* All Rights Reserved. http://www.opengeospatial.org/ogc/legal
*
* Permission to use, copy, and modify this software and its documentation, with
* or without modification, for any purpose and without fee or royalty is hereby
* granted, provided that you include the following on ALL copies of the software
* and documentation or portions thereof, including modifications, that you make:
*
* 1. The full text of this NOTICE in a location viewable to users of the
* redistributed or derivative work.
* 2. Notice of any changes or modifications to the OGC files, including the
* date changes were made.
*
* THIS SOFTWARE AND DOCUMENTATION IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE
* NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT
* THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY
* PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.
*
* COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR
* CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR DOCUMENTATION.
*
* The name and trademarks of copyright holders may NOT be used in advertising or
* publicity pertaining to the software without specific, written prior permission.
* Title to copyright in this software and any associated documentation will at all
* times remain with copyright holders.
*/
/**
* {@linkplain org.opengis.metadata.quality.DataQuality Data quality} and
* {@linkplain org.opengis.metadata.quality.PositionalAccuracy positional accuracy}.
* The following is adapted from
* {@linkplain org.opengis.annotation.Specification#ISO_19111 OpenGIS® Spatial Referencing by
* Coordinates (Topic 2)} specification.
*
* The parameters that define a coordinate reference system
* are chosen rather than measured to satisfy the degrees-of-freedom problem in
* the changeover from observation to coordinate quantities. Coordinate reference
* systems are therefore by definition error-free (i.e., non-stochastic).
* A coordinate reference system is realised through a network of control points.
* The coordinates of those control points, derived from surface and/or from
* satellite observations, are stochastic. Their accuracy can be expressed in a
* covariance matrix, which, due to the degrees-of-freedom problem, will have a
* rank deficiency, described in geodetic literature.
*
* Coordinate transformations between coordinate reference
* systems usually have parameter values derived from two sets of point coordinates,
* one set in system 1, the other set in system 2. As these coordinates are stochastic
* (i.e., have random-error characteristics) the derived transformation parameter
* values will also be stochastic. Their covariance matrix can be calculated.
*
* Coordinates that have not been "naturally" determined in
* coordinate reference system 2, but have been determined in coordinate system 1
* and then transformed to system 2, have the random error effects of the
* transformation superimposed on their original error characteristics. It may be
* possible in well-controlled cases to calculate the covariance matrices of the
* point coordinates before and after the transformation, and thus isolate the
* effect of the transformation, but in practice a user will only be interested
* in the accuracy of the final transformed coordinates.
*
* Nevertheless the option is offered to specify the
* covariance matrix of point coordinates resulting exclusively from the
* transformation. It is outside the scope of this specification to describe
* how that covariance matrix should be used. Because a covariance matrix is
* symmetrical, only the upper or lower diagonal part (including the main diagonal)
* needs to be specified.
*
* For some transformations, this accuracy information is
* compacted in some assessment of an average impact on horizontal position and
* vertical position, allowing specification of average absolute accuracy and,
* when relevant and available, average relative accuracy. Hence separate quality
* measures may be specified for horizontal and for vertical position in those
* objects.
*
* @author Martin Desruisseaux (IRD)
* @author Cory Horner (Refractions Research)
* @author Cédric Briançon (Geomatys)
* @version 3.0
* @since 2.0
*/
package org.opengis.metadata.quality;