gbox_centroid()

int gbox_centroid	(	const GBOX *	gbox,
		POINT2D *	out
	)

Computes the average(ish) center of the box and returns success.

Definition at line 267 of file lwgeodetic.c.

References cart2geog(), GEOGRAPHIC_POINT::lat, latitude_degrees_normalize(), GEOGRAPHIC_POINT::lon, longitude_degrees_normalize(), LW_SUCCESS, normalize(), rad2deg, POINT2D::x, POINT3D::x, GBOX::xmin, POINT2D::y, POINT3D::y, and POINT3D::z.

Referenced by geography_bestsrid(), and test_gbox_utils().

{
        double d[6];
        GEOGRAPHIC_POINT g;
        POINT3D pt;
        int i;

        /* Take a copy of the box corners so we can treat them as a list */
        /* Elements are xmin, xmax, ymin, ymax, zmin, zmax */
        memcpy(d, &(gbox->xmin), 6*sizeof(double));

        /* Zero out our return vector */
        pt.x = pt.y = pt.z = 0.0;

        for ( i = 0; i < 8; i++ )
        {
                POINT3D pt_n;

                pt_n.x = d[i / 4];
                pt_n.y = d[2 + ((i % 4) / 2)];
                pt_n.z = d[4 + (i % 2)];
                normalize(&pt_n);

                pt.x += pt_n.x;
                pt.y += pt_n.y;
                pt.z += pt_n.z;
        }

        pt.x /= 8.0;
        pt.y /= 8.0;
        pt.z /= 8.0;
        normalize(&pt);

        cart2geog(&pt, &g);
        out->x = longitude_degrees_normalize(rad2deg(g.lon));
        out->y = latitude_degrees_normalize(rad2deg(g.lat));

        return LW_SUCCESS;
}

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