GRASS GIS 8 Programmer's Manual
8.5.0dev(2024)-847944e18e
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GIS Library - Window overlap functions. More...
#include <grass/gis.h>
Go to the source code of this file.
Functions | |
int | G_window_overlap (const struct Cell_head *window, double N, double S, double E, double W) |
Determines if a box overlays a map window. More... | |
double | G_window_percentage_overlap (const struct Cell_head *window, double N, double S, double E, double W) |
Determines percentage of box is contained in the window. More... | |
GIS Library - Window overlap functions.
(C) 2001-2014 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.
Definition in file wind_overlap.c.
int G_window_overlap | ( | const struct Cell_head * | window, |
double | N, | ||
double | S, | ||
double | E, | ||
double | W | ||
) |
Determines if a box overlays a map window.
Given a map window, and a box of N,S,E,W does the box overlap the map window?
Note: knows about global wrap-around for lat-long.
[in] | window | pointer to window structure |
[in] | N | north |
[in] | S | south |
[in] | E | east |
[in] | W | west |
Definition at line 35 of file wind_overlap.c.
double G_window_percentage_overlap | ( | const struct Cell_head * | window, |
double | N, | ||
double | S, | ||
double | E, | ||
double | W | ||
) |
Determines percentage of box is contained in the window.
This version returns the percentage (from 0 to 1) of the box contained in the window. This feature can be used during vector plotting to decide if it is more efficient to do a level-one read of the whole vector map, or to pay the price of a level-two startup so only those arcs that enter the window are actually read.
[in] | window | pointer to widnow structure |
[in] | N | north |
[in] | S | south |
[in] | E | east |
[in] | W | west |
Definition at line 80 of file wind_overlap.c.