LWGEOM_line_interpolate_point()

Datum LWGEOM_line_interpolate_point

(

PG_FUNCTION_ARGS

)

Definition at line 184 of file lwgeom_functions_analytic.c.

{
        GSERIALIZED *gser = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *result;
        double distance_fraction = PG_GETARG_FLOAT8(1);
        int repeat = PG_NARGS() > 2 && PG_GETARG_BOOL(2);
        int srid = gserialized_get_srid(gser);
        LWLINE* lwline;
        LWGEOM* lwresult;
        POINTARRAY* opa;
 
        if ( distance_fraction < 0 || distance_fraction > 1 )
        {
                elog(ERROR,"line_interpolate_point: 2nd arg isn't within [0,1]");
                PG_FREE_IF_COPY(gser, 0);
                PG_RETURN_NULL();
        }
 
        if ( gserialized_get_type(gser) != LINETYPE )
        {
                elog(ERROR,"line_interpolate_point: 1st arg isn't a line");
                PG_FREE_IF_COPY(gser, 0);
                PG_RETURN_NULL();
        }
 
        lwline = lwgeom_as_lwline(lwgeom_from_gserialized(gser));
        opa = lwline_interpolate_points(lwline, distance_fraction, repeat);
 
        lwgeom_free(lwline_as_lwgeom(lwline));
        PG_FREE_IF_COPY(gser, 0);
 
        if (opa->npoints <= 1)
        {
                lwresult = lwpoint_as_lwgeom(lwpoint_construct(srid, NULL, opa));
        } else {
                lwresult = lwmpoint_as_lwgeom(lwmpoint_construct(srid, opa));
        }
 
        result = geometry_serialize(lwresult);
        lwgeom_free(lwresult);
 
        PG_RETURN_POINTER(result);
}

References geometry_serialize(), gserialized_get_srid(), gserialized_get_type(), LINETYPE, lwgeom_as_lwline(), lwgeom_free(), lwgeom_from_gserialized(), lwline_as_lwgeom(), lwline_interpolate_points(), lwmpoint_as_lwgeom(), lwmpoint_construct(), lwpoint_as_lwgeom(), lwpoint_construct(), and POINTARRAY::npoints.

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