lwgeom_make_valid()

LWGEOM * lwgeom_make_valid

(

LWGEOM *

geom

)

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

Definition at line 854 of file liblwgeom/lwgeom_geos_clean.c.

{
        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, 1);
        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;
        }
 
#if POSTGIS_GEOS_VERSION < 38
        geosout = LWGEOM_GEOS_makeValid(geosgeom);
#else
        geosout = GEOSMakeValid(geosgeom);
#endif
        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;
}

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

Referenced by _lwt_AddLineEdge(), lwgeom_clean(), mvt_safe_clip_polygon_by_box(), rt_raster_gdal_polygonize(), rt_raster_surface(), ST_MakeValid(), test_geos_makevalid(), and test_lwgeom_make_valid().

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