extend.c File Reference

Vedit library - extend lines (adopted from break.c) More...

#include <math.h>
#include <grass/vedit.h>

Include dependency graph for extend.c:

Go to the source code of this file.

Macros
#define	TOL   1e-9

Functions
int	Vedit_extend_lines (struct Map_info *Map, struct ilist *List, int nodes, int parallel, double thresh)
	Extend lines in given threshold. More...

Detailed Description

Vedit library - extend lines (adopted from break.c)

(C) 2017 by the GRASS Development Team

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Author

Huidae Cho <grass4u gmail.com>

Definition in file extend.c.

Macro Definition Documentation

TOL

#define TOL   1e-9

Definition at line 17 of file extend.c.

Function Documentation

Vedit_extend_lines()

int Vedit_extend_lines	(	struct Map_info *	Map,
		struct ilist *	List,
		int	nodes,
		int	parallel,
		double	thresh
	)

Extend lines in given threshold.

1. Extend first line only
        \                      \
   id1   \             ->       \
                                 \
   id2 ----------            -----+----


2. Extend both lines
        \                      \
   id1   \             ->       \
                                 \
   id2        ---                 +----


3. Extend first line when both are on the same line
   id1 ---    --- id2  ->    -----+----


4. Connect two parallel lines (parallel=1)
   id1 ------                -------
                       ->         /
   id2     ------                +-----


5. Don't connect two parallel lines (parallel=0)
   id1 ------                ------
                       ->
   id2     ------                ------

Parameters

Map	pointer to Map_info
List	list of selected lines
nodes	1 for start node, 2 for end node, other for both
parallel	connect parallel lines
thresh	threshold value

Returns

number of modified lines

Definition at line 68 of file extend.c.

References ilist::n_values, and Vect_new_list().