sample.c File Reference

GIS library - sampling methods (extract a cell value from raster map) More...

#include <string.h>
#include <unistd.h>
#include <math.h>
#include <grass/gis.h>
#include <grass/glocale.h>

Include dependency graph for sample.c:

Go to the source code of this file.

Functions
DCELL	G_get_raster_sample (int fd, const struct Cell_head *window, struct Categories *cats, double north, double east, int usedesc, INTERP_TYPE itype)
	Extract a cell value from raster map. More...
DCELL	G_get_raster_sample_nearest (int fd, const struct Cell_head *window, struct Categories *cats, double north, double east, int usedesc)
DCELL	G_get_raster_sample_bilinear (int fd, const struct Cell_head *window, struct Categories *cats, double north, double east, int usedesc)
DCELL	G_get_raster_sample_cubic (int fd, const struct Cell_head *window, struct Categories *cats, double north, double east, int usedesc)

Detailed Description

GIS library - sampling methods (extract a cell value from raster map)

1/2006: moved to libgis from v.sample/v.drape for clone removal

(C) 2001-2008 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

James Darrell McCauley <darrell mccauley-usa.com>, http://mccauley-usa.com/

Date

1994

Definition in file sample.c.

Function Documentation

DCELL G_get_raster_sample	(	int	fd,
		const struct Cell_head *	window,
		struct Categories *	cats,
		double	north,
		double	east,
		int	usedesc,
		INTERP_TYPE	itype
	)

Extract a cell value from raster map.

Extract a cell value from raster map at given northing and easting with a sampled 3x3 window using a specified interpolation method.

Parameters

fd	file descriptor
window	region settings
cats	categories
north	northing position
east	easting position
usedesc	flag to scan category label
itype	interpolation method

Returns

cell value at given position

Definition at line 50 of file sample.c.

References G_fatal_error(), G_get_raster_sample_bilinear(), G_get_raster_sample_cubic(), and G_get_raster_sample_nearest().

DCELL G_get_raster_sample_bilinear	(	int	fd,
		const struct Cell_head *	window,
		struct Categories *	cats,
		double	north,
		double	east,
		int	usedesc
	)

Definition at line 122 of file sample.c.

References buf, G_allocate_d_raster_buf(), G_easting_to_col(), G_free(), G_get_cat(), G_get_d_raster_row(), G_interp_bilinear(), G_is_d_null_value(), G_northing_to_row(), G_set_d_null_value(), G_squeeze(), G_window_cols(), G_window_rows(), grid, and int.

Referenced by G_get_raster_sample().

DCELL G_get_raster_sample_cubic	(	int	fd,
		const struct Cell_head *	window,
		struct Categories *	cats,
		double	north,
		double	east,
		int	usedesc
	)

Definition at line 197 of file sample.c.

References buf, G_allocate_d_raster_buf(), G_easting_to_col(), G_free(), G_get_cat(), G_get_d_raster_row(), G_interp_bicubic(), G_is_d_null_value(), G_northing_to_row(), G_set_d_null_value(), G_squeeze(), G_window_cols(), G_window_rows(), grid, and int.

Referenced by G_get_raster_sample().

DCELL G_get_raster_sample_nearest	(	int	fd,
		const struct Cell_head *	window,
		struct Categories *	cats,
		double	north,
		double	east,
		int	usedesc
	)

Definition at line 78 of file sample.c.

References buf, G_allocate_d_raster_buf(), G_easting_to_col(), G_free(), G_get_cat(), G_get_d_raster_row(), G_is_d_null_value(), G_northing_to_row(), G_set_d_null_value(), G_squeeze(), G_window_cols(), G_window_rows(), and int.

Referenced by G_get_raster_sample().