Example #1
0
func Polygon(g *geos.Geos, nodes []element.Node) (*geos.Geom, error) {
	nodes = unduplicateNodes(nodes)
	if len(nodes) < 4 {
		return nil, ErrorNoRing
	}

	coordSeq, err := g.CreateCoordSeq(uint32(len(nodes)), 2)
	if err != nil {
		return nil, err
	}

	// coordSeq inherited by LinearRing, no destroy
	for i, nd := range nodes {
		err := coordSeq.SetXY(g, uint32(i), nd.Long, nd.Lat)
		if err != nil {
			return nil, err
		}
	}
	ring, err := coordSeq.AsLinearRing(g)
	if err != nil {
		// coordSeq gets Destroy by GEOS
		return nil, err
	}
	// ring inherited by Polygon, no destroy

	geom := g.Polygon(ring, nil)
	if geom == nil {
		g.Destroy(ring)
		return nil, errors.New("unable to create polygon")
	}
	g.DestroyLater(geom)
	return geom, nil
}
Example #2
0
func geosRing(g *geos.Geos, ls geojson.LineString) (*geos.Geom, error) {
	coordSeq, err := g.CreateCoordSeq(uint32(len(ls)), 2)
	if err != nil {
		return nil, err
	}

	// coordSeq inherited by LinearRing, no destroy
	for i, p := range ls {
		err := coordSeq.SetXY(g, uint32(i), p.Long, p.Lat)
		if err != nil {
			return nil, err
		}
	}
	ring, err := coordSeq.AsLinearRing(g)
	if err != nil {
		// coordSeq gets Destroy by GEOS
		return nil, err
	}

	return ring, nil
}
Example #3
0
func LineString(g *geos.Geos, nodes []element.Node) (*geos.Geom, error) {
	nodes = unduplicateNodes(nodes)
	if len(nodes) < 2 {
		return nil, ErrorOneNodeWay
	}

	coordSeq, err := g.CreateCoordSeq(uint32(len(nodes)), 2)
	if err != nil {
		return nil, err
	}
	// coordSeq inherited by LineString
	for i, nd := range nodes {
		coordSeq.SetXY(g, uint32(i), nd.Long, nd.Lat)
	}
	geom, err := coordSeq.AsLineString(g)
	if err != nil {
		// coordSeq gets Destroy by GEOS
		return nil, err
	}
	g.DestroyLater(geom)
	return geom, nil
}