GRASS GIS 7 Programmer's Manual
7.9.dev(2021)e5379bbd7

GIS Library  Sphereical area calculation routines. More...
Go to the source code of this file.
Functions  
void  G_begin_zone_area_on_sphere (double r, double s) 
Initialize calculations for sphere. More...  
double  G_darea0_on_sphere (double lat) 
Calculates integral for area between two latitudes. More...  
double  G_area_for_zone_on_sphere (double north, double south) 
Calculates area between latitudes. More...  
GIS Library  Sphereical area calculation routines.
(C) 20012009 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 area_sphere.c.
double G_area_for_zone_on_sphere  (  double  north, 
double  south  
) 
Calculates area between latitudes.
This routine shows how to calculate area between two lats, but isn't efficient for row by row since G_darea0_on_sphere() will be called twice for the same lat, once as a south then again as a north.
Returns the area between latitudes north and south scaled by the factor s passed to G_begin_zone_area_on_sphere().
north  
[in]  south 
Definition at line 70 of file area_sphere.c.
References G_darea0_on_sphere().
void G_begin_zone_area_on_sphere  (  double  r, 
double  s  
) 
Initialize calculations for sphere.
Initializes raster area calculations for a sphere. The radius of the sphere is r and s is a scale factor to allow for calculations of a part of the zone (see G_begin_zone_area_on_ellipsoid()).
r  radius of sphere 
s  scale factor 
Definition at line 36 of file area_sphere.c.
double G_darea0_on_sphere  (  double  lat  ) 
Calculates integral for area between two latitudes.
lat  latitude 
Definition at line 48 of file area_sphere.c.
References Radians.
Referenced by G_area_for_zone_on_sphere().