/*
* 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.geometry.coordinate;
import org.opengis.annotation.UML;
import static org.opengis.annotation.Obligation.*;
import static org.opengis.annotation.Specification.*;
/**
* A {@linkplain ParametricCurveSurface parametric curve surface} defined from a rectangular grid
* in the parameter space. The rows from this grid are control points for horizontal surface curves;
* the columns are control points for vertical surface curves. The working assumption is that for a
* pair of parametric coordinates (<var>s</var>, <var>t</var>), that the horizontal curves for
* each integer offset are calculated and evaluated at <var>s</var>. This defines a sequence of
* control points:
*
* <blockquote>
* <c<sub>n</sub>(<var>s</var>) : <var>s</var> = 1 … columns>
* </blockquote>
*
* From this sequence, a vertical curve is calculated for <var>s</var>, and evaluated at <var>t</var>.
* In most cases, the order of calculation (horizontal-vertical versus vertical-horizontal) does not
* make a difference. Where it does, the horizontal-vertical order shall be the one used.
* <p>
* The most common case of a gridded surface is a 2D spline. In this case the weight functions for
* each parameter make order of calculation unimportant:
*
* <blockquote>TODO: copy equations there</blockquote>
*
* Logically, any pair of curve interpolation types can lead to a subtype of {@code GriddedSurface}.
* The sub-interfaces provided in this package define some of the most commonly encountered surfaces
* that can be represented in this manner.
*
*
* @source $URL: http://svn.osgeo.org/geotools/branches/2.7.x/modules/library/opengis/src/main/java/org/opengis/geometry/coordinate/GriddedSurface.java $
* @version <A HREF="http://www.opengeospatial.org/standards/as">ISO 19107</A>
* @author Martin Desruisseaux (IRD)
* @since GeoAPI 2.0
*/
@UML(identifier="GM_GriddedSurface", specification=ISO_19107)
public interface GriddedSurface extends ParametricCurveSurface {
/**
* Returns the doubly indexed sequence of control points, given in row major form.
* There is no assumption made about the shape of the grid. For example, the positions
* need not effect a "2½D" surface, consecutive points may be equal in any or
* all of their ordinates. Further, the curves in either or both directions may close.
*/
@UML(identifier="controlPoint", obligation=MANDATORY, specification=ISO_19107)
PointGrid getControlPoints();
/**
* Returns the number of rows in the parameter grid.
*/
@UML(identifier="rows", obligation=MANDATORY, specification=ISO_19107)
int getRows();
/**
* Returns the number of columns in the parameter grid.
*/
@UML(identifier="columns", obligation=MANDATORY, specification=ISO_19107)
int getColumns();
}