circ_center_spherical()

static int circ_center_spherical ( const GEOGRAPHIC_POINT *  c1, const GEOGRAPHIC_POINT *  c2, double  distance, double  offset, GEOGRAPHIC_POINT *  center  )

static

Given the centers of two circles, and the offset distance we want to put the new center between them (calculated as the distance implied by the radii of the inputs and the distance between the centers) figure out where the new center point is, by getting the direction from c1 to c2 and projecting from c1 in that direction by the offset distance.

Definition at line 165 of file lwgeodetic_tree.c.

References LW_FAILURE, LWDEBUGF, sphere_direction(), and sphere_project().

Referenced by circ_node_internal_new().

{
        /* Direction from c1 to c2 */
        double dir = sphere_direction(c1, c2, distance);

        LWDEBUGF(4,"calculating spherical center", dir);

        LWDEBUGF(4,"dir is %g", dir);

        /* Catch sphere_direction when it barfs */
        if ( isnan(dir) )
                return LW_FAILURE;

        /* Center of new circle is projection from start point, using offset distance*/
        return sphere_project(c1, offset, dir, center);
}

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