lwgeom_make_valid()

LWGEOM* lwgeom_make_valid

(

LWGEOM *

geom

)

Attempts to make an invalid geometries valid w/out losing points.

NOTE: this is only available when liblwgeom is built against GEOS 3.3.0 or higher

Definition at line 982 of file liblwgeom/lwgeom_geos_clean.c.

References LWGEOM::bbox, LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), lwalloc(), lwcollection_construct(), LWDEBUG, LWDEBUGF, lwerror(), LWGEOM2GEOS(), lwgeom_geos_errmsg, lwgeom_geos_error(), LWGEOM_GEOS_makeValid(), lwgeom_is_collection(), lwgeom_make_geos_friendly(), MULTITYPE, LWGEOM::srid, and LWGEOM::type.

Referenced by _lwt_AddLineEdge(), _lwt_EdgeMotionArea(), lwgeom_clean(), mvt_geom(), rt_raster_gdal_polygonize(), rt_raster_surface(), ST_MakeValid(), and test_lwgeom_make_valid().

{
        int is3d;
        GEOSGeom geosgeom;
        GEOSGeometry* geosout;
        LWGEOM *lwgeom_out;

        is3d = FLAGS_GET_Z(lwgeom_in->flags);

        /*
         * Step 1 : try to convert to GEOS, if impossible, clean that up first
         *          otherwise (adding only duplicates of existing points)
         */

        initGEOS(lwgeom_geos_error, lwgeom_geos_error);

        lwgeom_out = lwgeom_in;
        geosgeom = LWGEOM2GEOS(lwgeom_out, 0);
        if ( ! geosgeom )
        {
                LWDEBUGF(4,
                               "Original geom can't be converted to GEOS (%s)"
                               " - will try cleaning that up first",
                               lwgeom_geos_errmsg);


                lwgeom_out = lwgeom_make_geos_friendly(lwgeom_out);
                if ( ! lwgeom_out )
                {
                        lwerror("Could not make a valid geometry out of input");
                }

                /* try again as we did cleanup now */
                /* TODO: invoke LWGEOM2GEOS directly with autoclean ? */
                geosgeom = LWGEOM2GEOS(lwgeom_out, 0);
                if ( ! geosgeom )
                {
                        lwerror("Couldn't convert POSTGIS geom to GEOS: %s",
                                lwgeom_geos_errmsg);
                        return NULL;
                }

        }
        else
        {
                LWDEBUG(4, "original geom converted to GEOS");
                lwgeom_out = lwgeom_in;
        }

        geosout = LWGEOM_GEOS_makeValid(geosgeom);
        GEOSGeom_destroy(geosgeom);
        if ( ! geosout )
        {
                return NULL;
        }

        lwgeom_out = GEOS2LWGEOM(geosout, is3d);
        GEOSGeom_destroy(geosout);

        if ( lwgeom_is_collection(lwgeom_in) && ! lwgeom_is_collection(lwgeom_out) )
        {{
                LWGEOM **ogeoms = lwalloc(sizeof(LWGEOM*));
                LWGEOM *ogeom;
                LWDEBUG(3, "lwgeom_make_valid: forcing multi");
                /* NOTE: this is safe because lwgeom_out is surely not lwgeom_in or
                 * otherwise we couldn't have a collection and a non-collection */
                assert(lwgeom_in != lwgeom_out);
                ogeoms[0] = lwgeom_out;
                ogeom = (LWGEOM *)lwcollection_construct(MULTITYPE[lwgeom_out->type],
                                          lwgeom_out->srid, lwgeom_out->bbox, 1, ogeoms);
                lwgeom_out->bbox = NULL;
                lwgeom_out = ogeom;
        }}

        lwgeom_out->srid = lwgeom_in->srid;
        return lwgeom_out;
}

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