1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
/**
* \file align_window.c
*
* \brief GIS Library - Window alignment functions.
*
* (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 GRASS GIS Development Team
*
* \date 1999-2008
*/
#include <stdio.h>
#include <math.h>
#include <grass/gis.h>
/**
* \brief Align two regions.
*
* Modifies the input <b>window</b> to align to
* <b>ref</b> region. The resolutions in <b>window</b> are set to match those
* in <b>ref</b> and the <b>window</b> edges (north, south, east, west) are
* modified to align with the grid of the <b>ref</b> region.
* The <b>window</b> may be enlarged if necessary to achieve the alignment.
* The north is rounded northward, the south southward, the east eastward and the
* west westward. Lon-lon constraints are taken into consideration
* to make sure that the north doesn't go above 90 degrees (for lat/lon)
* or that the east does "wrap" past the west, etc.
*
* \param[in,out] window
* \param[in] ref
* \return NULL on success
* \return Pointer to an error string on failure
*/
char *G_align_window(struct Cell_head *window, const struct Cell_head *ref)
{
int preserve;
window->ns_res = ref->ns_res;
window->ew_res = ref->ew_res;
window->zone = ref->zone;
window->proj = ref->proj;
preserve = window->proj == PROJECTION_LL &&
window->east == (window->west + 360);
window->south =
G_row_to_northing(ceil(G_northing_to_row(window->south, ref)), ref);
window->north =
G_row_to_northing(floor(G_northing_to_row(window->north, ref)), ref);
window->east =
G_col_to_easting(ceil(G_easting_to_col(window->east, ref)), ref);
window->west =
G_col_to_easting(floor(G_easting_to_col(window->west, ref)), ref);
if (window->proj == PROJECTION_LL) {
while (window->north > 90.0)
window->north -= window->ns_res;
while (window->south < -90.0)
window->south += window->ns_res;
if (preserve)
window->east = window->west + 360;
else
while (window->east - window->west > 360.0)
window->east -= window->ew_res;
}
return G_adjust_Cell_head(window, 0, 0);
}
|
