read_nat.c File Reference

Vector library - reading features (native format) More...

#include <sys/types.h>
#include <grass/vector.h>
#include <grass/glocale.h>

Include dependency graph for read_nat.c:

Go to the source code of this file.

Functions
int	V1_read_line_nat (struct Map_info *Map, struct line_pnts *Points, struct line_cats *Cats, off_t offset)
	Read vector feature on non-topological level (level 1) - native format - internal use only. More...
int	V1_read_next_line_nat (struct Map_info *Map, struct line_pnts *line_p, struct line_cats *line_c)
	Read next vector feature on non-topological level (level 1) - native format - internal use only. More...
int	V2_read_line_nat (struct Map_info *Map, struct line_pnts *line_p, struct line_cats *line_c, int line)
	Read vector feature on topological level (level 2) - native format - internal use only. More...
int	V2_read_next_line_nat (struct Map_info *Map, struct line_pnts *line_p, struct line_cats *line_c)
	Read next vector feature on topological level (level 2) - native format - internal use only. More...

Detailed Description

Vector library - reading features (native format)

Higher level functions for reading/writing/manipulating vectors.

(C) 2001-2009, 2011-2012 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

Original author CERL, probably Dave Gerdes or Mike Higgins.

Update to GRASS 5.7 by Radim Blazek and David D. Gray.

Update to GRASS 7 by Martin Landa <landa.martin gmail.com>

Definition in file read_nat.c.

Function Documentation

V1_read_line_nat()

int V1_read_line_nat	(	struct Map_info *	Map,
		struct line_pnts *	Points,
		struct line_cats *	Cats,
		off_t	offset
	)

Read vector feature on non-topological level (level 1) - native format - internal use only.

This function implements random access for native format, constraints are ignored!

Parameters

	Map	pointer to Map_info struct
[out]	Points	container used to store line points within (pointer to line_pnts struct)
[out]	Cats	container used to store line categories within (pointer to line_cats struct)
	offset	given offset

Returns

feature type (GV_POINT, GV_LINE, ...)

0 dead line

-2 nothing to read

-1 on failure

Definition at line 43 of file read_nat.c.

V1_read_next_line_nat()

int V1_read_next_line_nat	(	struct Map_info *	Map,
		struct line_pnts *	line_p,
		struct line_cats *	line_c
	)

Read next vector feature on non-topological level (level 1) - native format - internal use only.

This function implements sequential access, constraints are reflected, see Vect_set_constraint_region(), Vect_set_constraint_type(), or Vect_set_constraint_field().

Dead features are skipped.

Vect_rewind() can be used to reset reading.

Parameters

	Map	pointer to Map_info struct
[out]	line_p	container used to store line points within (pointer to line_pnts struct)
[out]	line_c	container used to store line categories within (pointer to line_cats struct)

Returns

feature type (GV_POINT, GV_LINE, ...)

0 dead line

-2 nothing to read

-1 on failure

Definition at line 72 of file read_nat.c.

References Map_info::constraint, Map_info::dig_fp, dig_ftell(), G_debug(), Map_info::region_flag, TRUE, and Vect_get_constraint_box().

V2_read_line_nat()

int V2_read_line_nat	(	struct Map_info *	Map,
		struct line_pnts *	line_p,
		struct line_cats *	line_c,
		int	line
	)

Read vector feature on topological level (level 2) - native format - internal use only.

This function implements random access for native format, constraints are ignored!

Note: Topology must be built at level >= GV_BUILD_BASE

Parameters

	Map	pointer to Map_info struct
[out]	Points	container used to store line points within (pointer to line_pnts struct)
[out]	Cats	container used to store line categories within (pointer to line_cats struct)
	line	feature id to read (starts at 1)

Returns

feature type (GV_POINT, GV_LINE, ...)

-2 nothing to read

-1 on failure

Definition at line 136 of file read_nat.c.

V2_read_next_line_nat()

int V2_read_next_line_nat	(	struct Map_info *	Map,
		struct line_pnts *	line_p,
		struct line_cats *	line_c
	)

Read next vector feature on topological level (level 2) - native format - internal use only.

This function implements sequential access, constraints are reflected, see Vect_set_constraint_region(), Vect_set_constraint_type(), or Vect_set_constraint_field().

Use Vect_rewind() to reset reading.

Dead feature are skipped.

Parameters

	Map	pointer to Map_info struct
[out]	line_p	container used to store line points within (pointer to line_pnts struct)
[out]	line_c	container used to store line categories within (pointer to line_cats struct)

Returns

feature type (GV_POINT, GV_LINE, ...)

-2 nothing to read

-1 on error

Definition at line 178 of file read_nat.c.