ptarray_locate_along()

static POINTARRAY * ptarray_locate_along ( const POINTARRAY *  pa, double  m, double  offset  )

static

Definition at line 78 of file lwlinearreferencing.c.

{
        uint32_t i;
        POINT4D p1, p2, pn;
        POINTARRAY *dpa = NULL;
 
        /* Can't do anything with degenerate point arrays */
        if (!pa || pa->npoints < 2)
                return NULL;
 
        /* Walk through each segment in the point array */
        for (i = 1; i < pa->npoints; i++)
        {
                getPoint4d_p(pa, i - 1, &p1);
                getPoint4d_p(pa, i, &p2);
 
                /* No derived point? Move to next segment. */
                if (segment_locate_along(&p1, &p2, m, offset, &pn) == LW_FALSE)
                        continue;
 
                /* No pointarray, make a fresh one */
                if (dpa == NULL)
                        dpa = ptarray_construct_empty(ptarray_has_z(pa), ptarray_has_m(pa), 8);
 
                /* Add our new point to the array */
                ptarray_append_point(dpa, &pn, 0);
        }
 
        return dpa;
}

References getPoint4d_p(), LW_FALSE, POINTARRAY::npoints, ptarray_append_point(), ptarray_construct_empty(), ptarray_has_m(), ptarray_has_z(), and segment_locate_along().

Referenced by lwline_locate_along().

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