Used to intersect a line segment with any number of polygons in 2D. Returns the intersected polygons in order along with t values. May be an alternative to SurfaceIter and feiTraverseLineSegment2. More...

Inheritance diagram for xms::GmMultiPolyIntersectorImpl:

Public Member Functions
	GmMultiPolyIntersectorImpl (const VecPt3d &a_points, const VecInt2d &a_polys, BSHP< GmMultiPolyIntersectionSorter > a_sorter, int a_startingId=1)
	constructor More...

virtual void	SetQuery (GmMultiPolyIntersectorQueryEnum a_query) override
	Set the query to use (covered by, intersects...). More...

virtual void	TraverseLineSegment (double x1, double y1, double x2, double y2, VecInt &polyids, VecDbl &tvalues) override
	Intersect segment with polys and save intersected polys and t-values. More...

virtual void	TraverseLineSegment (double x1, double y1, double x2, double y2, VecInt &polyids) override
	Intersect segment with polys and save intersected polys. More...

virtual void	TraverseLineSegment (double a_x1, double a_y1, double a_x2, double a_y2, VecInt &a_polyids, std::vector< Pt3d > &a_pts) override
	Intersect segment with polys and save intersected polys and intersection points. More...

virtual int	PolygonFromPoint (const Pt3d &a_pt) override
	Finds the polygon containing the point. More...

Private Member Functions
void	CalculateBuffer ()
	Calculate a small buffer distance by which we expand all polygon bounding boxes.

void	BufferTheBox (GmBstBox3d &box) const
	Because the rtree intersection fails in some cases where the line is on an edge, we slightly expand the bounding box of the poly to ensure that it comes back as a potential intersection. This may result in more false positives but until boost geometry starts working correctly, it's the best idea we've got. More...

GmBstPoly3d &	GetBoostPoly (int a_polyIdx)
	Create and return a boost polygon given a polygon index. More...

void	BuildBoostPoly (int a_polyIdx, GmBstPoly3d &a_boostPoly) const
	Build a boost polygon given a polygon index. More...

void	BuildRTree ()
	Create a boost rtree of polygon extents.

void	CreateLine ()
	Creates a boost geom line of the current line segment.

void	GetPolysForPoint (Pt3d pt, SetInt &poly)
	Find the set of polygons intersected (in or on) by the point. More...

void	EnsureEndPointsRepresented ()
	Because unfortunately intersecting the line with the poly doesn't always create an intersection if a point is on the polygon edge.

void	IntersectEachPolyWithLine ()
	Go through results (potential polygons) and intersect each one.

void	ComputeTValues ()
	Compute t values (0.0 - 1.0) from the intersection. More...

void	SortIntersections ()
	Does a preliminary sort of the intersections by t value.

void	OffsetPolyIds (VecInt &polyIds) const
	If polygon IDs should start at something other than 1, we handle that here. More...

void	PointsOnSegment (const GmBstPoly3d &a_poly, const GmBstLine3d &a_line, std::deque< Pt3d > &a_output)
	Check if the points on the outside of the polygon lie on the line segment. More...

void	TraverseLineSegmentAll (double a_x1, double a_y1, double a_x2, double a_y2, VecInt &a_polyids, VecDbl &a_tvalues, std::vector< Pt3d > &a_pts)
	Intersect segment with polys and save intersected polys, t-values, and intersection points. More...

Private Attributes
GmMultiPolyIntersectorData	m_d
	Point and poly data.

Pt3d	m_pt1
	1st line segment point

Pt3d	m_pt2
	2nd line segment point

RtreeBox *	m_rtree
	Rtree used to find polygons.

GmBstLine3d	m_line
	Current line segment.

double	m_buffer
	Small buffer around each bounding box.

int	m_startingId
	Offset if polys start at something other than one.

std::vector< GmBstPoly3d >	m_boostPolys
	Polygons as boost geom polygons.

BSHP < GmMultiPolyIntersectionSorter >	m_sorter
	Sorter used to process results.

GmMultiPolyIntersectorQueryEnum	m_query
	Type of query (intersect, covered by...)

Additional Inherited Members
Static Public Member Functions inherited from xms::GmMultiPolyIntersector
static boost::shared_ptr < GmMultiPolyIntersector >	New (const std::vector< Pt3d > &a_points, const std::vector< std::vector< int > > &a_polys, boost::shared_ptr< GmMultiPolyIntersectionSorter > a_sorter, int a_startingId=1)
	Creates a new GmMultiPolyIntersectorImpl object. More...

Detailed Description

Used to intersect a line segment with any number of polygons in 2D. Returns the intersected polygons in order along with t values. May be an alternative to SurfaceIter and feiTraverseLineSegment2.

Definition at line 61 of file GmMultiPolyIntersector.cpp.

Constructor & Destructor Documentation

xms::GmMultiPolyIntersectorImpl::GmMultiPolyIntersectorImpl	(	const VecPt3d &	a_points,
		const VecInt2d &	a_polys,
		BSHP< GmMultiPolyIntersectionSorter >	a_sorter,
		int	a_startingId = `1`
	)

constructor

Parameters

a_points	The points that make up the polygon.
a_polys	0-based indexes into a_points array to define polygons. The first point is NOT repeated as the last point.
a_sorter	Class to clean up and sort the intersections the way you want them.
a_startingId	If the polygon IDs should start at something other than 1, specify the starting value.

Definition at line 164 of file GmMultiPolyIntersector.cpp.

References BuildRTree(), CalculateBuffer(), m_boostPolys, m_d, xms::GmMultiPolyIntersectorData::m_points, and xms::GmMultiPolyIntersectorData::m_polys.

Member Function Documentation

void xms::GmMultiPolyIntersectorImpl::BufferTheBox ( GmBstBox3d & box ) const

private

Because the rtree intersection fails in some cases where the line is on an edge, we slightly expand the bounding box of the poly to ensure that it comes back as a potential intersection. This may result in more false positives but until boost geometry starts working correctly, it's the best idea we've got.

Parameters

box The box.

Definition at line 227 of file GmMultiPolyIntersector.cpp.

References m_buffer.

Referenced by BuildRTree().

void xms::GmMultiPolyIntersectorImpl::BuildBoostPoly	(	int	a_polyIdx,
		GmBstPoly3d &	a_boostPoly
	)		const

private

Build a boost polygon given a polygon index.

Parameters

a_polyIdx	The polygon index.
a_boostPoly	GmBstPoly3d.

Definition at line 250 of file GmMultiPolyIntersector.cpp.

References m_d, xms::GmMultiPolyIntersectorData::m_points, and xms::GmMultiPolyIntersectorData::m_polys.

Referenced by GetBoostPoly().

void xms::GmMultiPolyIntersectorImpl::ComputeTValues ( )

private

Compute t values (0.0 - 1.0) from the intersection.

t values are the percent (0.0 - 1.0) distance from the line segment start to each intersection.

Definition at line 394 of file GmMultiPolyIntersector.cpp.

References m_d, xms::GmMultiPolyIntersectorData::m_ixs, m_pt1, m_pt2, and XM_NODATA.

Referenced by TraverseLineSegmentAll().

GmBstPoly3d & xms::GmMultiPolyIntersectorImpl::GetBoostPoly ( int a_polyIdx )

private

Create and return a boost polygon given a polygon index.

Parameters

a_polyIdx The polygon index.

Returns: GmBstPoly3d.

Definition at line 238 of file GmMultiPolyIntersector.cpp.

References BuildBoostPoly(), and m_boostPolys.

Referenced by GetPolysForPoint(), and IntersectEachPolyWithLine().

void xms::GmMultiPolyIntersectorImpl::GetPolysForPoint	(	Pt3d	pt,
		SetInt &	a_poly
	)

private

Find the set of polygons intersected (in or on) by the point.

Parameters

pt	point loction
a_poly	1-based polygon ID.

Definition at line 310 of file GmMultiPolyIntersector.cpp.

References GetBoostPoly(), m_query, m_rtree, and XM_ASSERT.

Referenced by PolygonFromPoint(), and TraverseLineSegmentAll().

void xms::GmMultiPolyIntersectorImpl::OffsetPolyIds ( VecInt & polyIds ) const

private

If polygon IDs should start at something other than 1, we handle that here.

Parameters

polyIds 1-based list of polygons intersected by line segment.

Definition at line 449 of file GmMultiPolyIntersector.cpp.

References m_startingId, and XM_NONE.

Referenced by TraverseLineSegmentAll().

void xms::GmMultiPolyIntersectorImpl::PointsOnSegment	(	const GmBstPoly3d &	a_poly,
		const GmBstLine3d &	a_line,
		std::deque< Pt3d > &	a_output
	)

private

Check if the points on the outside of the polygon lie on the line segment.

Parameters

a_poly	GmBstPoly3d.
a_line	GmBstLine3d.
a_output	Output.

Definition at line 369 of file GmMultiPolyIntersector.cpp.

References m_buffer, xms::Pt3< T >::x, and xms::Pt3< T >::y.

Referenced by IntersectEachPolyWithLine().

int xms::GmMultiPolyIntersectorImpl::PolygonFromPoint ( const Pt3d & a_pt )

overridevirtual

Finds the polygon containing the point.

Parameters

a_pt	the location of the point

Returns: the polygon id

Definition at line 519 of file GmMultiPolyIntersector.cpp.

References GetPolysForPoint(), and XM_NONE.

void xms::GmMultiPolyIntersectorImpl::SetQuery ( GmMultiPolyIntersectorQueryEnum a_query )

overridevirtual

Set the query to use (covered by, intersects...).

Parameters

a_query GmMultiPolyIntersectorQueryEnum

Definition at line 301 of file GmMultiPolyIntersector.cpp.

References m_query.

void xms::GmMultiPolyIntersectorImpl::TraverseLineSegment	(	double	x1,
		double	y1,
		double	x2,
		double	y2,
		VecInt &	polyids,
		VecDbl &	tvalues
	)

overridevirtual

Intersect segment with polys and save intersected polys and t-values.

Parameters

x1	x coordinate of 1st point defining a line segment.
y1	y coordinate of 1st point defining a line segment.
x2	x coordinate of 2nd point defining a line segment.
y2	y coordinate of 2nd point defining a line segment.
polyids	1-based list of polygons intersected by line segment.
tvalues	Values from 0.0 to 1.0 representing where on the line segment the intersection with the polygon in polyids occurs. If there are any t values there are always at least 2 and all represent where the line enters the polygon, except the last which represents where it exited. There would therefore be one more t value than poly id but we make the sizes equal by always making the last poly id -1.

Definition at line 475 of file GmMultiPolyIntersector.cpp.

References TraverseLineSegmentAll().

void xms::GmMultiPolyIntersectorImpl::TraverseLineSegment	(	double	x1,
		double	y1,
		double	x2,
		double	y2,
		VecInt &	polyids
	)

overridevirtual

Intersect segment with polys and save intersected polys.

Parameters

x1	x coordinate of 1st point defining a line segment.
y1	y coordinate of 1st point defining a line segment.
x2	x coordinate of 2nd point defining a line segment.
y2	y coordinate of 2nd point defining a line segment.
polyids	1-based list of polygons intersected by line segment.

Definition at line 490 of file GmMultiPolyIntersector.cpp.

References TraverseLineSegmentAll().

void xms::GmMultiPolyIntersectorImpl::TraverseLineSegment	(	double	a_x1,
		double	a_y1,
		double	a_x2,
		double	a_y2,
		VecInt &	a_polyids,
		std::vector< Pt3d > &	a_pts
	)

overridevirtual

Intersect segment with polys and save intersected polys and intersection points.

Parameters

a_x1	x coordinate of 1st point defining a line segment.
a_y1	y coordinate of 1st point defining a line segment.
a_x2	x coordinate of 2nd point defining a line segment.
a_y2	y coordinate of 2nd point defining a line segment.
a_polyids	1-based list of polygons intersected by line segment.
a_pts	Intersection points.

Definition at line 507 of file GmMultiPolyIntersector.cpp.

References TraverseLineSegmentAll().

void xms::GmMultiPolyIntersectorImpl::TraverseLineSegmentAll	(	double	a_x1,
		double	a_y1,
		double	a_x2,
		double	a_y2,
		VecInt &	a_polyids,
		VecDbl &	a_tvalues,
		std::vector< Pt3d > &	a_pts
	)

private

Intersect segment with polys and save intersected polys, t-values, and intersection points.

Parameters

a_x1	x coordinate of 1st point defining a line segment.
a_y1	y coordinate of 1st point defining a line segment.
a_x2	x coordinate of 2nd point defining a line segment.
a_y2	y coordinate of 2nd point defining a line segment.
a_polyids	1-based list of polygons intersected by line segment.
a_tvalues	Values from 0.0 to 1.0 representing where on the line segment the intersection with the polygon in polyids occurs. If there are any t values there are always at least 2 and all represent where the line enters the polygon, except the last which represents where it exited. There would therefore be one more t value than poly id but we make the sizes equal by always making the last poly id -1.
a_pts	Intersection points.

Definition at line 546 of file GmMultiPolyIntersector.cpp.

References ComputeTValues(), CreateLine(), EnsureEndPointsRepresented(), GetPolysForPoint(), IntersectEachPolyWithLine(), m_d, xms::GmMultiPolyIntersectorData::m_ixs, m_line, xms::GmMultiPolyIntersectorData::m_polys1, xms::GmMultiPolyIntersectorData::m_polys2, m_pt1, m_pt2, m_sorter, OffsetPolyIds(), xms::Pt3< T >::Set(), SortIntersections(), and XM_ASSERT.

Referenced by TraverseLineSegment().

The documentation for this class was generated from the following file:

/home/travis/build/Aquaveo/xmsgeom/xmsgeom/geometry/GmMultiPolyIntersector.cpp

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation