lwgeom_boundary()

LWGEOM* lwgeom_boundary

(

LWGEOM *

lwgeom

)

Definition at line 2686 of file lwgeom.c.

{
        int32_t srid = lwgeom_get_srid(lwgeom);
        uint8_t hasz = lwgeom_has_z(lwgeom);
        uint8_t hasm = lwgeom_has_m(lwgeom);
 
        switch (lwgeom->type)
        {
        case POINTTYPE:
        case MULTIPOINTTYPE: {
                return lwgeom_construct_empty(lwgeom->type, srid, hasz, hasm);
        }
        case LINETYPE:
        case CIRCSTRINGTYPE: {
                if (lwgeom_is_closed(lwgeom) || lwgeom_is_empty(lwgeom))
                        return (LWGEOM *)lwmpoint_construct_empty(srid, hasz, hasm);
                else
                {
                        LWLINE *lwline = (LWLINE *)lwgeom;
                        LWMPOINT *lwmpoint = lwmpoint_construct_empty(srid, hasz, hasm);
                        POINT4D pt;
                        getPoint4d_p(lwline->points, 0, &pt);
                        lwmpoint_add_lwpoint(lwmpoint, lwpoint_make(srid, hasz, hasm, &pt));
                        getPoint4d_p(lwline->points, lwline->points->npoints - 1, &pt);
                        lwmpoint_add_lwpoint(lwmpoint, lwpoint_make(srid, hasz, hasm, &pt));
 
                        return (LWGEOM *)lwmpoint;
                }
        }
        case MULTILINETYPE:
        case MULTICURVETYPE: {
                LWMLINE *lwmline = (LWMLINE *)lwgeom;
                POINT4D *out = lwalloc(sizeof(POINT4D) * lwmline->ngeoms * 2);
                uint32_t n = 0;
 
                for (uint32_t i = 0; i < lwmline->ngeoms; i++)
                {
                        LWMPOINT *points = lwgeom_as_lwmpoint(lwgeom_boundary((LWGEOM *)lwmline->geoms[i]));
                        if (!points)
                                continue;
 
                        for (uint32_t k = 0; k < points->ngeoms; k++)
                        {
                                POINT4D pt = getPoint4d(points->geoms[k]->point, 0);
 
                                uint8_t seen = LW_FALSE;
                                for (uint32_t j = 0; j < n; j++)
                                {
                                        if (memcmp(&(out[j]), &pt, sizeof(POINT4D)) == 0)
                                        {
                                                seen = LW_TRUE;
                                                out[j] = out[--n];
                                                break;
                                        }
                                }
                                if (!seen)
                                        out[n++] = pt;
                        }
 
                        lwgeom_free((LWGEOM *)points);
                }
 
                LWMPOINT *lwmpoint = lwmpoint_construct_empty(srid, hasz, hasm);
 
                for (uint32_t i = 0; i < n; i++)
                        lwmpoint_add_lwpoint(lwmpoint, lwpoint_make(srid, hasz, hasm, &(out[i])));
 
                lwfree(out);
 
                return (LWGEOM *)lwmpoint;
        }
        case TRIANGLETYPE: {
                LWTRIANGLE *lwtriangle = (LWTRIANGLE *)lwgeom;
                POINTARRAY *points = ptarray_clone_deep(lwtriangle->points);
                return (LWGEOM *)lwline_construct(srid, 0, points);
        }
        case POLYGONTYPE: {
                LWPOLY *lwpoly = (LWPOLY *)lwgeom;
 
                LWMLINE *lwmline = lwmline_construct_empty(srid, hasz, hasm);
                for (uint32_t i = 0; i < lwpoly->nrings; i++)
                {
                        POINTARRAY *ring = ptarray_clone_deep(lwpoly->rings[i]);
                        lwmline_add_lwline(lwmline, lwline_construct(srid, 0, ring));
                }
 
                /* Homogenize the multilinestring to hopefully get a single LINESTRING */
                LWGEOM *lwout = lwgeom_homogenize((LWGEOM *)lwmline);
                lwgeom_free((LWGEOM *)lwmline);
                return lwout;
        }
        case CURVEPOLYTYPE: {
                LWCURVEPOLY *lwcurvepoly = (LWCURVEPOLY *)lwgeom;
                LWCOLLECTION *lwcol = lwcollection_construct_empty(MULTICURVETYPE, srid, hasz, hasm);
 
                for (uint32_t i = 0; i < lwcurvepoly->nrings; i++)
                        lwcol = lwcollection_add_lwgeom(lwcol, lwgeom_clone_deep(lwcurvepoly->rings[i]));
 
                return (LWGEOM *)lwcol;
        }
        case MULTIPOLYGONTYPE:
        case COLLECTIONTYPE:
        case TINTYPE: {
                LWCOLLECTION *lwcol = (LWCOLLECTION *)lwgeom;
                LWCOLLECTION *lwcol_boundary = lwcollection_construct_empty(COLLECTIONTYPE, srid, hasz, hasm);
 
                for (uint32_t i = 0; i < lwcol->ngeoms; i++)
                        lwcollection_add_lwgeom(lwcol_boundary, lwgeom_boundary(lwcol->geoms[i]));
 
                LWGEOM *lwout = lwgeom_homogenize((LWGEOM *)lwcol_boundary);
                lwgeom_free((LWGEOM *)lwcol_boundary);
 
                return lwout;
        }
        default:
                lwerror("%s: unsupported geometry type: %s", __func__, lwtype_name(lwgeom->type));
                return NULL;
        }
}

References CIRCSTRINGTYPE, COLLECTIONTYPE, CURVEPOLYTYPE, LWMPOINT::geoms, LWMLINE::geoms, LWCOLLECTION::geoms, getPoint4d(), getPoint4d_p(), LINETYPE, LW_FALSE, LW_TRUE, lwalloc(), lwcollection_add_lwgeom(), lwcollection_construct_empty(), lwerror(), lwfree(), lwgeom_as_lwmpoint(), lwgeom_boundary(), lwgeom_clone_deep(), lwgeom_construct_empty(), lwgeom_free(), lwgeom_get_srid(), lwgeom_has_m(), lwgeom_has_z(), lwgeom_homogenize(), lwgeom_is_closed(), lwgeom_is_empty(), lwline_construct(), lwmline_add_lwline(), lwmline_construct_empty(), lwmpoint_add_lwpoint(), lwmpoint_construct_empty(), lwpoint_make(), lwtype_name(), MULTICURVETYPE, MULTILINETYPE, MULTIPOINTTYPE, MULTIPOLYGONTYPE, LWMPOINT::ngeoms, LWMLINE::ngeoms, LWCOLLECTION::ngeoms, POINTARRAY::npoints, LWPOLY::nrings, LWCURVEPOLY::nrings, LWPOINT::point, LWLINE::points, LWTRIANGLE::points, POINTTYPE, POLYGONTYPE, ptarray_clone_deep(), LWPOLY::rings, LWCURVEPOLY::rings, TINTYPE, TRIANGLETYPE, and LWGEOM::type.

Referenced by boundary(), and lwgeom_boundary().

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