lwline_locate_along()

static LWMPOINT* lwline_locate_along ( const LWLINE *  lwline, double  m, double  offset  )

static

Definition at line 110 of file lwlinearreferencing.c.

{
        POINTARRAY *opa = NULL;
        LWMPOINT *mp = NULL;
        LWGEOM *lwg = lwline_as_lwgeom(lwline);
        int hasz, hasm, srid;
 
        /* Return degenerates upwards */
        if ( ! lwline ) return NULL;
 
        /* Create empty return shell */
        srid = lwgeom_get_srid(lwg);
        hasz = lwgeom_has_z(lwg);
        hasm = lwgeom_has_m(lwg);
 
        if ( hasm )
        {
                /* Find points along */
                opa = ptarray_locate_along(lwline->points, m, offset);
        }
        else
        {
                LWLINE *lwline_measured = lwline_measured_from_lwline(lwline, 0.0, 1.0);
                opa = ptarray_locate_along(lwline_measured->points, m, offset);
                lwline_free(lwline_measured);
        }
 
        /* Return NULL as EMPTY */
        if ( ! opa )
                return lwmpoint_construct_empty(srid, hasz, hasm);
 
        /* Convert pointarray into a multipoint */
        mp = lwmpoint_construct(srid, opa);
        ptarray_free(opa);
        return mp;
}

References lwgeom_get_srid(), lwgeom_has_m(), lwgeom_has_z(), lwline_as_lwgeom(), lwline_free(), lwline_measured_from_lwline(), lwmpoint_construct(), lwmpoint_construct_empty(), LWLINE::points, ptarray_free(), and ptarray_locate_along().

Referenced by lwgeom_locate_along(), and lwmline_locate_along().

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