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package orb
// Geometry is an interface that represents the shared attributes
// of a geometry.
type Geometry interface {
GeoJSONType() string
Dimensions() int // e.g. 0d, 1d, 2d
Bound() Bound
// requiring because sub package type switch over all possible types.
private()
}
// compile time checks
var (
_ Geometry = Point{}
_ Geometry = MultiPoint{}
_ Geometry = LineString{}
_ Geometry = MultiLineString{}
_ Geometry = Ring{}
_ Geometry = Polygon{}
_ Geometry = MultiPolygon{}
_ Geometry = Bound{}
_ Geometry = Collection{}
)
func (p Point) private() {}
func (mp MultiPoint) private() {}
func (ls LineString) private() {}
func (mls MultiLineString) private() {}
func (r Ring) private() {}
func (p Polygon) private() {}
func (mp MultiPolygon) private() {}
func (b Bound) private() {}
func (c Collection) private() {}
// AllGeometries lists all possible types and values that a geometry
// interface can be. It should be used only for testing to verify
// functions that accept a Geometry will work in all cases.
var AllGeometries = []Geometry{
nil,
Point{},
MultiPoint{},
LineString{},
MultiLineString{},
Ring{},
Polygon{},
MultiPolygon{},
Bound{},
Collection{},
// nil values
MultiPoint(nil),
LineString(nil),
MultiLineString(nil),
Ring(nil),
Polygon(nil),
MultiPolygon(nil),
Collection(nil),
// Collection of Collection
Collection{Collection{Point{}}},
}
// A Collection is a collection of geometries that is also a Geometry.
type Collection []Geometry
// GeoJSONType returns the geometry collection type.
func (c Collection) GeoJSONType() string {
return "GeometryCollection"
}
// Dimensions returns the max of the dimensions of the collection.
func (c Collection) Dimensions() int {
max := -1
for _, g := range c {
if d := g.Dimensions(); d > max {
max = d
}
}
return max
}
// Bound returns the bounding box of all the Geometries combined.
func (c Collection) Bound() Bound {
if len(c) == 0 {
return emptyBound
}
var b Bound
start := -1
for i, g := range c {
if g != nil {
start = i
b = g.Bound()
break
}
}
if start == -1 {
return emptyBound
}
for i := start + 1; i < len(c); i++ {
if c[i] == nil {
continue
}
b = b.Union(c[i].Bound())
}
return b
}
// Equal compares two collections. Returns true if lengths are the same
// and all the sub geometries are the same and in the same order.
func (c Collection) Equal(collection Collection) bool {
if len(c) != len(collection) {
return false
}
for i, g := range c {
if !Equal(g, collection[i]) {
return false
}
}
return true
}
// Clone returns a deep copy of the collection.
func (c Collection) Clone() Collection {
if c == nil {
return nil
}
nc := make(Collection, len(c))
for i, g := range c {
nc[i] = Clone(g)
}
return nc
}
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