func SplitPolygonAtGrid(g *geos.Geos, geom *geos.Geom, gridWidth, currentGridWidth float64) ([]*geos.Geom, error) {
var result []*geos.Geom
geomBounds := geom.Bounds()
if geomBounds == geos.NilBounds {
return nil, errors.New("couldn't create bounds for geom")
}
for _, bounds := range tileBounds(geom.Bounds(), currentGridWidth) {
clipGeom := g.BoundsPolygon(bounds)
if clipGeom == nil {
return nil, errors.New("couldn't create bounds polygon")
}
part := g.Intersection(geom, clipGeom)
g.Destroy(clipGeom)
if part == nil {
return nil, errors.New("couldn't create intersection")
}
if !g.IsEmpty(part) && strings.HasSuffix(g.Type(part), "Polygon") {
if gridWidth >= currentGridWidth {
result = append(result, part)
} else {
moreParts, err := SplitPolygonAtGrid(g, part, gridWidth, currentGridWidth/2.0)
g.Destroy(part)
if err != nil {
return nil, err
}
result = append(result, moreParts...)
}
}
}
return result, nil
}
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
}
func geosPolygon(g *geos.Geos, polygon polygon) (*geos.Geom, error) {
if len(polygon) == 0 {
return nil, errors.New("empty polygon")
}
shell, err := geosRing(g, polygon[0])
if err != nil {
return nil, err
}
holes := make([]*geos.Geom, len(polygon)-1)
for i, ls := range polygon[1:] {
hole, err := geosRing(g, ls)
if err != nil {
return nil, err
}
holes[i] = hole
}
geom := g.Polygon(shell, holes)
if geom == nil {
g.Destroy(shell)
for _, hole := range holes {
g.Destroy(hole)
}
return nil, errors.New("unable to create polygon")
}
return geom, nil
}
func destroyRings(g *geos.Geos, rings []*Ring) {
for _, r := range rings {
if r.geom != nil {
g.Destroy(r.geom)
r.geom = nil
}
}
}
func filterInvalidLineStrings(g *geos.Geos, geoms []*geos.Geom) []*geos.Geom {
var result []*geos.Geom
for _, geom := range geoms {
if geom.Length() > 1e-9 {
result = append(result, geom)
} else {
g.Destroy(geom)
}
}
return result
}
func flattenLineStrings(g *geos.Geos, geoms []*geos.Geom) []*geos.Geom {
var result []*geos.Geom
for _, geom := range geoms {
if g.Type(geom) == "MultiLineString" {
for _, part := range g.Geoms(geom) {
result = append(result, g.Clone(part))
}
g.Destroy(geom)
} else if g.Type(geom) == "LineString" {
result = append(result, geom)
} else {
log.Printf("unexpected geometry type in flattenPolygons")
g.Destroy(geom)
}
}
return result
}
func (c *Limiter) IntersectsBuffer(g *geos.Geos, x, y float64) bool {
if c.bufferedPrep == nil {
return true
}
if x < c.bufferedBbox.MinX ||
y < c.bufferedBbox.MinY ||
x > c.bufferedBbox.MaxX ||
y > c.bufferedBbox.MaxY {
return false
}
p := g.Point(x, y)
if p == nil {
return false
}
defer g.Destroy(p)
c.bufferedPrepMu.Lock()
defer c.bufferedPrepMu.Unlock()
return g.PreparedIntersects(c.bufferedPrep, p)
}
func filterGeometryByType(g *geos.Geos, geom *geos.Geom, targetType string) []*geos.Geom {
// Filter (multi)geometry for compatible `geom_type`,
// because we can't insert points into linestring tables for example
geomType := g.Type(geom)
if geomType == targetType {
// same type is fine
return []*geos.Geom{geom}
}
if geomType == "Polygon" && targetType == "MultiPolygon" {
// multipolygon mappings also support polygons
return []*geos.Geom{geom}
}
if geomType == "MultiPolygon" && targetType == "Polygon" {
// polygon mappings should also support multipolygons
return []*geos.Geom{geom}
}
if g.NumGeoms(geom) >= 1 {
// GeometryCollection or MultiLineString? return list of geometries
var geoms []*geos.Geom
for _, part := range g.Geoms(geom) {
// only parts with same type
if g.Type(part) == targetType {
geoms = append(geoms, g.Clone(part))
}
}
g.Destroy(geom)
if len(geoms) != 0 {
return geoms
}
return []*geos.Geom{}
}
g.Destroy(geom)
return []*geos.Geom{}
}