/********************************************************************** * * GEOS - Geometry Engine Open Source * http://geos.osgeo.org * * Copyright (C) 2005-2006 Refractions Research Inc. * Copyright (C) 2001-2002 Vivid Solutions Inc. * * This is free software; you can redistribute and/or modify it under * the terms of the GNU Lesser General Public Licence as published * by the Free Software Foundation. * See the COPYING file for more information. * ********************************************************************** * * Last port: linearref/LengthIndexOfPoint.java rev. 1.10 * **********************************************************************/ #ifndef GEOS_LINEARREF_LENGTHINDEXOFPOINT_H #define GEOS_LINEARREF_LENGTHINDEXOFPOINT_H #include #include #include #include #include namespace geos { namespace linearref // geos::linearref { /** * \brief * Computes the length index of the point * on a linear Geometry nearest a given Coordinate. * * The nearest point is not necessarily unique; this class * always computes the nearest point closest to * the start of the geometry. */ class LengthIndexOfPoint { private: const geom::Geometry *linearGeom; double indexOfFromStart(const geom::Coordinate& inputPt, const double minIndex) const; double segmentNearestMeasure(const geom::LineSegment *seg, const geom::Coordinate& inputPt, double segmentStartMeasure) const; public: static double indexOf(const geom::Geometry *linearGeom, const geom::Coordinate& inputPt); static double indexOfAfter(const geom::Geometry *linearGeom, const geom::Coordinate& inputPt, double minIndex); LengthIndexOfPoint(const geom::Geometry *linearGeom); /** * Find the nearest location along a linear Geometry to a given point. * * @param inputPt the coordinate to locate * @return the location of the nearest point */ double indexOf(const geom::Coordinate& inputPt) const; /** \brief * Finds the nearest index along the linear Geometry * to a given Coordinate after the specified minimum index. * * If possible the location returned will be strictly greater than the * minLocation. * If this is not possible, the * value returned will equal minLocation. * (An example where this is not possible is when * minLocation = [end of line] ). * * @param inputPt the coordinate to locate * @param minLocation the minimum location for the point location * @return the location of the nearest point */ double indexOfAfter(const geom::Coordinate& inputPt, double minIndex) const; }; } } #endif