geography_dwithin()

Datum geography_dwithin

(

PG_FUNCTION_ARGS

)

Definition at line 276 of file geography_measurement.c.

{
        GSERIALIZED *g1 = NULL;
        GSERIALIZED *g2 = NULL;
        double tolerance = 0.0;
        double distance;
        bool use_spheroid = true;
        SPHEROID s;
        int dwithin = LW_FALSE;
 
        /* Get our geometry objects loaded into memory. */
        g1 = PG_GETARG_GSERIALIZED_P(0);
        g2 = PG_GETARG_GSERIALIZED_P(1);
 
        /* Read our tolerance value. */
        if ( PG_NARGS() > 2 && ! PG_ARGISNULL(2) )
                tolerance = PG_GETARG_FLOAT8(2);
 
        /* Read our calculation type. */
        if ( PG_NARGS() > 3 && ! PG_ARGISNULL(3) )
                use_spheroid = PG_GETARG_BOOL(3);
 
        error_if_srid_mismatch(gserialized_get_srid(g1), gserialized_get_srid(g2));
 
        /* Initialize spheroid */
        spheroid_init_from_srid(fcinfo, gserialized_get_srid(g1), &s);
 
        /* Set to sphere if requested */
        if ( ! use_spheroid )
                s.a = s.b = s.radius;
 
        /* Return FALSE on empty arguments. */
        if ( gserialized_is_empty(g1) || gserialized_is_empty(g2) )
        {
                PG_FREE_IF_COPY(g1, 0);
                PG_FREE_IF_COPY(g2, 1);
                PG_RETURN_BOOL(false);
        }
 
        /* Do the brute force calculation if the cached calculation doesn't tick over */
        if ( LW_FAILURE == geography_dwithin_cache(fcinfo, g1, g2, &s, tolerance, &dwithin) )
        {
                LWGEOM* lwgeom1 = lwgeom_from_gserialized(g1);
                LWGEOM* lwgeom2 = lwgeom_from_gserialized(g2);
                distance = lwgeom_distance_spheroid(lwgeom1, lwgeom2, &s, tolerance);
                /* Something went wrong... */
                if ( distance < 0.0 )
                        elog(ERROR, "lwgeom_distance_spheroid returned negative!");
                dwithin = (distance <= tolerance);
                lwgeom_free(lwgeom1);
                lwgeom_free(lwgeom2);
        }
 
        /* Clean up */
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);
 
        PG_RETURN_BOOL(dwithin);
}

References distance(), error_if_srid_mismatch(), geography_dwithin_cache(), gserialized_get_srid(), gserialized_is_empty(), LW_FAILURE, LW_FALSE, lwgeom_distance_spheroid(), lwgeom_free(), lwgeom_from_gserialized(), and s.

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