gserialized_distance_nd()

Datum gserialized_distance_nd

(

PG_FUNCTION_ARGS

)

Definition at line 808 of file gserialized_gist_nd.c.

{
        char b1mem[GIDX_MAX_SIZE];
        GIDX *b1 = (GIDX*)b1mem;
        char b2mem[GIDX_MAX_SIZE];
        GIDX *b2 = (GIDX*)b2mem;
 
#if POSTGIS_PGSQL_VERSION < 95
 
        /* Centroid-to-centroid distance */
        Datum gs1 = PG_GETARG_DATUM(0);
        Datum gs2 = PG_GETARG_DATUM(1);
        double box_distance = FLT_MAX;
 
        /* Must be able to build box for each argument (ie, not empty geometry). */
        if ( (gserialized_datum_get_gidx_p(gs1, b1) == LW_SUCCESS) &&
             (gserialized_datum_get_gidx_p(gs2, b2) == LW_SUCCESS) )
        {
                box_distance = gidx_distance_leaf_centroid(b1, b2);
                POSTGIS_DEBUGF(3, "got boxes %s and %s", gidx_to_string(b1), gidx_to_string(b2));
        }
        PG_RETURN_FLOAT8(box_distance);
 
#else /* POSTGIS_PGSQL_VERSION >= 96 */
 
        /* Feature-to-feature distance */
        GSERIALIZED *geom1 = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *geom2 = PG_GETARG_GSERIALIZED_P(1);
        LWGEOM *lw1 = lwgeom_from_gserialized(geom1);
        LWGEOM *lw2 = lwgeom_from_gserialized(geom2);
        LWGEOM *closest;
        double distance;
 
 
        /* Find an exact shortest line w/ the dimensions we support */
        if ( lwgeom_has_z(lw1) && lwgeom_has_z(lw2) )
        {
                closest = lwgeom_closest_line_3d(lw1, lw2);
                distance = lwgeom_length(closest);
        }
        else
        {
                closest = lwgeom_closest_line(lw1, lw2);
                distance = lwgeom_length_2d(closest);
        }
 
        /* Un-sqrt the distance so we can add extra terms */
        distance = distance*distance;
 
        /* Can only add the M term if both objects have M */
        if ( lwgeom_has_m(lw1) && lwgeom_has_m(lw2) )
        {
                double m1 = 0, m2 = 0;
                int usebox = false;
 
                if ( lwgeom_get_type(lw1) == POINTTYPE )
                {
                        POINT4D p;
                        lwpoint_getPoint4d_p((LWPOINT*)lw1, &p);
                        m1 = p.m;
                }
                else if ( lwgeom_get_type(lw1) == LINETYPE )
                {
                        LWPOINT *lwp1 = lwline_get_lwpoint(lwgeom_as_lwline(closest), 0);
                        m1 = lwgeom_interpolate_point(lw1, lwp1);
                        lwpoint_free(lwp1);
                }
                else
                {
                        usebox = true;
                }
 
                if ( lwgeom_get_type(lw2) == POINTTYPE )
                {
                        POINT4D p;
                        lwpoint_getPoint4d_p((LWPOINT*)lw2, &p);
                        m2 = p.m;
                }
                else if ( lwgeom_get_type(lw2) == LINETYPE )
                {
                        LWPOINT *lwp2 = lwline_get_lwpoint(lwgeom_as_lwline(closest), 1);
                        m2 = lwgeom_interpolate_point(lw2, lwp2);
                        lwpoint_free(lwp2);
                }
                else
                {
                        usebox = true;
                }
 
                if ( usebox )
                {
                        double d;
                        gserialized_get_gidx_p(geom1, b1);
                        gserialized_get_gidx_p(geom2, b2);
                        d = gidx_distance_m(b1, b2);
                        distance += d*d;
                }
                else
                {
                        distance += (m2-m1)*(m2-m1);
                }
        }
 
        lwgeom_free(closest);
 
        PG_FREE_IF_COPY(geom1, 0);
        PG_FREE_IF_COPY(geom2, 1);
        PG_RETURN_FLOAT8(sqrt(distance));
#endif /* POSTGIS_PGSQL_VERSION >= 96 */
}

References distance(), gidx_distance_m(), LINETYPE, LW_SUCCESS, lwgeom_as_lwline(), lwgeom_closest_line(), lwgeom_closest_line_3d(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_get_type(), lwgeom_has_m(), lwgeom_has_z(), lwgeom_interpolate_point(), lwgeom_length(), lwgeom_length_2d(), lwline_get_lwpoint(), lwpoint_free(), lwpoint_getPoint4d_p(), POINT4D::m, and POINTTYPE.

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