intersect.c File Reference

#include <stdlib.h>
#include <math.h>
#include <grass/gis.h>
#include <grass/Vect.h>

Include dependency graph for intersect.c:

Go to the source code of this file.

Data Structures
struct	CROSS
Defines
#define	D   ((ax2-ax1)*(by1-by2) - (ay2-ay1)*(bx1-bx2))
#define	D1   ((bx1-ax1)*(by1-by2) - (by1-ay1)*(bx1-bx2))
#define	D2   ((ax2-ax1)*(by1-ay1) - (ay2-ay1)*(bx1-ax1))
Functions
int	Vect_segment_intersection (double ax1, double ay1, double az1, double ax2, double ay2, double az2, double bx1, double by1, double bz1, double bx2, double by2, double bz2, double *x1, double *y1, double *z1, double *x2, double *y2, double *z2, int with_z)
	check for intersect of 2 line segments
int	Vect_line_intersection (struct line_pnts *APoints, struct line_pnts *BPoints, struct line_pnts ***ALines, struct line_pnts ***BLines, int *nalines, int *nblines, int with_z)
int	Vect_line_check_intersection (struct line_pnts *APoints, struct line_pnts *BPoints, int with_z)
	Check if 2 lines intersect. Points (Points->n_points == 1) are also supported.

---

Define Documentation

#define D   ((ax2-ax1)*(by1-by2) - (ay2-ay1)*(bx1-bx2))

Definition at line 48 of file intersect.c.

#define D1   ((bx1-ax1)*(by1-by2) - (by1-ay1)*(bx1-bx2))

Definition at line 49 of file intersect.c.

#define D2   ((ax2-ax1)*(by1-ay1) - (ay2-ay1)*(bx1-ax1))

Definition at line 50 of file intersect.c.

---

Function Documentation

int Vect_line_check_intersection	(	struct line_pnts *	APoints,
		struct line_pnts *	BPoints,
		int	with_z
	)

Check if 2 lines intersect. Points (Points->n_points == 1) are also supported.

Returns:

0 no intersection

1 intersection found

Parameters:

	APoints	first input line
	BPoints	second input line
	with_z	3D, not supported (only if one or both are points) !

Definition at line 926 of file intersect.c.

References Rect::boundary, find_cross(), RTreeDestroyNode(), RTreeInsertRect(), RTreeNewIndex(), RTreeSearch(), and Vect_line_distance().

Referenced by Vect_select_lines_by_polygon().

int Vect_line_intersection	(	struct line_pnts *	APoints,
		struct line_pnts *	BPoints,
		struct line_pnts ***	ALines,
		struct line_pnts ***	BLines,
		int *	nalines,
		int *	nblines,
		int	with_z
	)

Definition at line 478 of file intersect.c.

References Rect::boundary, dig_line_degenerate(), CROSS::distance, RTreeDestroyNode(), RTreeInsertRect(), RTreeNewIndex(), RTreeSearch(), CROSS::segment, Vect_append_point(), Vect_destroy_line_struct(), Vect_new_line_struct(), CROSS::x, and CROSS::y.

Referenced by Vect_break_lines().

int Vect_segment_intersection	(	double	ax1,
		double	ay1,
		double	az1,
		double	ax2,
		double	ay2,
		double	az2,
		double	bx1,
		double	by1,
		double	bz1,
		double	bx2,
		double	by2,
		double	bz2,
		double *	x1,
		double *	y1,
		double *	z1,
		double *	x2,
		double *	y2,
		double *	z2,
		int	with_z
	)

check for intersect of 2 line segments

Returns:

0 - do not intersect, 1 - intersect at one point, 2 - partial overlap, 3 - a contains b, 4 - b contains a, 5 - identical

Parameters:

input

line a, input line b, intersection point1 (case 2-4), intersection point2 (case 2-4), use z coordinate (3D)

Definition at line 107 of file intersect.c.

References D, D1, and D2.