GIS Library - Window mapping functions. More...

#include <stdlib.h>
#include <grass/gis.h>
#include "G.h"

Include dependency graph for window_map.c:

Macros
#define	alloc_index(n) (COLUMN_MAPPING ) G_malloc((n)sizeof(COLUMN_MAPPING))

Functions
int	G__create_window_mapping (int fd)
	Create window mapping. More...

double	G_northing_to_row (double north, const struct Cell_head *window)
	Northing to row. More...

double	G_adjust_east_longitude (double east, double west)
	Adjust east longitude. More...

double	G_adjust_easting (double east, const struct Cell_head *window)
	Returns east larger than west. More...

double	G_easting_to_col (double east, const struct Cell_head *window)
	Easting to column. More...

double	G_row_to_northing (double row, const struct Cell_head *window)
	Row to northing. More...

double	G_col_to_easting (double col, const struct Cell_head *window)
	Column to easting. More...

int	G_window_rows (void)
	Number of rows in active window. More...

int	G_window_cols (void)
	Number of columns in active window. More...

int	G__init_window (void)
	Initialize window. More...

int	G_row_repeat_nomask (int fd, int row)
	Loops rows until mismatch?. More...

Detailed Description

GIS Library - Window mapping functions.

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

Author: GRASS GIS Development Team

Date: 1999-2008

Definition in file window_map.c.

Macro Definition Documentation

#define alloc_index ( n ) (COLUMN_MAPPING *) G_malloc((n)*sizeof(COLUMN_MAPPING))

Definition at line 22 of file window_map.c.

Referenced by G__create_window_mapping().

Function Documentation

int G__create_window_mapping ( int fd )

Create window mapping.

Creates mapping from cell header into window. The boundaries and resolution of the two spaces do not have to be the same or aligned in any way.

Parameters

[in] fd file descriptor

Returns: always returns 0

Definition at line 36 of file window_map.c.

References alloc_index, fileinfo::C1, fileinfo::C2, fileinfo::cellhd, fileinfo::col_map, fd, G__::fileinfo, G__init_window(), G_debug(), G_free(), fileinfo::open_mode, OPEN_OLD, and G__::window.

Referenced by G__open_cell_old(), and G_set_window().

int G__init_window ( void )

Initialize window.

Returns: always returns 0

Definition at line 320 of file window_map.c.

References G_get_window(), G__::window, and G__::window_set.

Referenced by G__create_window_mapping(), G__open_cell_old(), G_get_set_window(), G_window_cols(), and G_window_rows().

double G_adjust_east_longitude	(	double	east,
		double	west
	)

Adjust east longitude.

This routine returns an equivalent east that is larger, but no more than 360 larger than the west coordinate.
Note: This routine should be used only with latitude-longitude coordinates.

Parameters

[in,out]	east
[in]	west

Returns: east coordinate

Definition at line 149 of file window_map.c.

Referenced by G_adjust_easting().

double G_adjust_easting	(	double	east,
		const struct Cell_head *	window
	)

Returns east larger than west.

If the region projection is PROJECTION_LL, then this routine returns an equivalent east that is larger, but no more than 360 degrees larger, than the coordinate for the western edge of the region. Otherwise no adjustment is made and the original east is returned.

Parameters

[in,out]	east
[in]	window

Returns: east coordinate

Definition at line 174 of file window_map.c.

References G_adjust_east_longitude().

Referenced by G_easting_to_col(), G_plot_where_en(), G_plot_where_xy(), and G_site_in_region().

double G_col_to_easting	(	double	col,
		const struct Cell_head *	window
	)

Column to easting.

Converts a col relative to a window to an easting.
Note: col is a double:

col+0.0 will return the easting for the western edge of the column.
col+0.5 will return the easting for the center of the column.
col+1.0 will return the easting for the eastern edge of the column.

Parameters

[in]	col
[in]	window

Returns: east coordinate

Definition at line 243 of file window_map.c.

Referenced by G_align_window().

double G_easting_to_col	(	double	east,
		const struct Cell_head *	window
	)

Easting to column.

Converts east relative to a window to a column.
Note: The result is a double. Casting it to an int will give the column number.

Parameters

[in]	east
[in]	window

Returns: column id

Definition at line 198 of file window_map.c.

References G_adjust_easting().

Referenced by G_align_window(), G_get_raster_sample_bilinear(), G_get_raster_sample_cubic(), and G_get_raster_sample_nearest().

double G_northing_to_row	(	double	north,
		const struct Cell_head *	window
	)

Northing to row.

Converts a northing relative to a window to a row.
Note: The result is a double. Casting it to an integer will give the row number.

Parameters

[in]	north
[in]	window

Returns: row id

Definition at line 129 of file window_map.c.

Referenced by G_align_window(), G_get_raster_sample_bilinear(), G_get_raster_sample_cubic(), and G_get_raster_sample_nearest().

int G_row_repeat_nomask	(	int	fd,
		int	row
	)

Loops rows until mismatch?.

This routine works fine if the mask is not set. It may give incorrect results with a mask, since the mask row may have a different repeat value. The issue can be fixed by doing it for the mask as well and using the smaller value.

Parameters

[in]	fd	file descriptor
[in]	row	starting row

Returns: number of rows completed

Definition at line 344 of file window_map.c.

References fileinfo::C1, fileinfo::C2, count, fd, G__::fileinfo, and G__::window.

double G_row_to_northing	(	double	row,
		const struct Cell_head *	window
	)

Row to northing.

Converts a row relative to a window to a northing.
Note: row is a double:

row+0.0 will return the northing for the northern edge of the row.
row+0.5 will return the northing for the center of the row.
row+1.0 will return the northing for the southern edge of the row.
Note: The result is a double. Casting it to an int will give the column number.

Parameters

[in]	row
[in]	window

Returns: north coordinate

Definition at line 223 of file window_map.c.

Referenced by G_align_window().

int G_window_cols ( void )

Number of columns in active window.

These routines return the number of rows and columns (respectively) in the active module region. Before raster maps can be read or written, it is necessary to known how many rows and columns are in the active region. For example:

int nrows, cols;
int row, col; 
nrows = G_window_rows( ); 
ncols = G_window_cols( ); 
for (row = 0; row < nrows; row++)
{
<i>read</i> row ...
for (col = 0; col < ncols; col++)
{
process col ...
}
}

Returns: number of columns

Definition at line 306 of file window_map.c.

References G__init_window(), and G__::window.

Referenced by G_allocate_c_raster_buf(), G_allocate_cell_buf(), G_allocate_d_raster_buf(), G_allocate_f_raster_buf(), G_allocate_null_buf(), G_allocate_raster_buf(), G_get_raster_sample_bilinear(), G_get_raster_sample_cubic(), G_get_raster_sample_nearest(), G_zero_cell_buf(), G_zero_raster_buf(), and IL_output_2d().

int G_window_rows ( void )

Number of rows in active window.

This routine returns the number of rows in the active module window. Before raster files can be read or written, it is necessary to known how many rows are in the active window. For example:

int nrows, cols;
int row, col; 
nrows = G_window_rows( ); 
ncols = G_window_cols( ); 
for (row = 0; row < nrows; row++)
{
<i>read</i> row ...
for (col = 0; col < ncols; col++)
{
process col ...
}
}

Returns: number of rows

Definition at line 273 of file window_map.c.

References G__init_window(), and G__::window.

Referenced by G_get_raster_sample_bilinear(), G_get_raster_sample_cubic(), G_get_raster_sample_nearest(), and IL_output_2d().

Macros

Functions

Detailed Description

Macro Definition Documentation

Function Documentation