LWGEOM_GEOS_getPointN()

GEOSGeometry * LWGEOM_GEOS_getPointN	(	const GEOSGeometry *	g_in,
		uint32_t	n
	)

Definition at line 46 of file liblwgeom/lwgeom_geos_clean.c.

References lwcollection_make_geos_friendly(), lwline_make_geos_friendly(), lwpoly_make_geos_friendly(), and ring_make_geos_friendly().

Referenced by LWGEOM_GEOS_nodeLines().

{
        uint32_t dims;
        const GEOSCoordSequence* seq_in;
        GEOSCoordSeq seq_out;
        double val;
        uint32_t sz;
        int gn;
        GEOSGeometry* ret;

        switch ( GEOSGeomTypeId(g_in) )
        {
        case GEOS_MULTIPOINT:
        case GEOS_MULTILINESTRING:
        case GEOS_MULTIPOLYGON:
        case GEOS_GEOMETRYCOLLECTION:
        {
                for (gn=0; gn<GEOSGetNumGeometries(g_in); ++gn)
                {
                        const GEOSGeometry* g = GEOSGetGeometryN(g_in, gn);
                        ret = LWGEOM_GEOS_getPointN(g,n);
                        if ( ret ) return ret;
                }
                break;
        }

        case GEOS_POLYGON:
        {
                ret = LWGEOM_GEOS_getPointN(GEOSGetExteriorRing(g_in), n);
                if ( ret ) return ret;
                for (gn=0; gn<GEOSGetNumInteriorRings(g_in); ++gn)
                {
                        const GEOSGeometry* g = GEOSGetInteriorRingN(g_in, gn);
                        ret = LWGEOM_GEOS_getPointN(g, n);
                        if ( ret ) return ret;
                }
                break;
        }

        case GEOS_POINT:
        case GEOS_LINESTRING:
        case GEOS_LINEARRING:
                break;

        }

        seq_in = GEOSGeom_getCoordSeq(g_in);
        if ( ! seq_in ) return NULL;
        if ( ! GEOSCoordSeq_getSize(seq_in, &sz) ) return NULL;
        if ( ! sz ) return NULL;

        if ( ! GEOSCoordSeq_getDimensions(seq_in, &dims) ) return NULL;

        seq_out = GEOSCoordSeq_create(1, dims);
        if ( ! seq_out ) return NULL;

        if ( ! GEOSCoordSeq_getX(seq_in, n, &val) ) return NULL;
        if ( ! GEOSCoordSeq_setX(seq_out, n, val) ) return NULL;
        if ( ! GEOSCoordSeq_getY(seq_in, n, &val) ) return NULL;
        if ( ! GEOSCoordSeq_setY(seq_out, n, val) ) return NULL;
        if ( dims > 2 )
        {
                if ( ! GEOSCoordSeq_getZ(seq_in, n, &val) ) return NULL;
                if ( ! GEOSCoordSeq_setZ(seq_out, n, val) ) return NULL;
        }

        return GEOSGeom_createPoint(seq_out);
}

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