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#include "gis.h"
#include <stdio.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.
* This routine returns NULL if ok, otherwise it returns an error message
* (do NOT free this message).
*
* \param window
* \param ref
* \return char *
*/
char *
G_align_window (window, ref)
struct Cell_head *window, *ref;
{
int preserve;
double floor(), ceil();
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);
}
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