geography_distance_uncached()

Datum geography_distance_uncached

(

PG_FUNCTION_ARGS

)

Definition at line 133 of file geography_measurement.c.

References SPHEROID::a, SPHEROID::b, distance(), error_if_srid_mismatch(), FP_TOLERANCE, geography_distance(), gserialized_get_srid(), lwgeom_add_bbox_deep(), lwgeom_distance_spheroid(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_is_empty(), PG_FUNCTION_INFO_V1(), SPHEROID::radius, and s.

Referenced by geography_distance_knn().

{
        LWGEOM *lwgeom1 = NULL;
        LWGEOM *lwgeom2 = NULL;
        GSERIALIZED *g1 = NULL;
        GSERIALIZED *g2 = NULL;
        double distance;
        double tolerance = FP_TOLERANCE;
        bool use_spheroid = true;
        SPHEROID s;

        /* 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;

        lwgeom1 = lwgeom_from_gserialized(g1);
        lwgeom2 = lwgeom_from_gserialized(g2);

        /* Return NULL on empty arguments. */
        if ( lwgeom_is_empty(lwgeom1) || lwgeom_is_empty(lwgeom2) )
        {
                PG_FREE_IF_COPY(g1, 0);
                PG_FREE_IF_COPY(g2, 1);
                PG_RETURN_NULL();
        }

        /* Make sure we have boxes attached */
        lwgeom_add_bbox_deep(lwgeom1, NULL);
        lwgeom_add_bbox_deep(lwgeom2, NULL);

        distance = lwgeom_distance_spheroid(lwgeom1, lwgeom2, &s, tolerance);

        POSTGIS_DEBUGF(2, "[GIST] '%s' got distance %g", __func__, distance);

        /* Clean up */
        lwgeom_free(lwgeom1);
        lwgeom_free(lwgeom2);
        PG_FREE_IF_COPY(g1, 0);
        PG_FREE_IF_COPY(g2, 1);

        /* Something went wrong, negative return... should already be eloged, return NULL */
        if ( distance < 0.0 )
        {
                PG_RETURN_NULL();
        }

        PG_RETURN_FLOAT8(distance);
}

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