tile38/geojson/linestring.go

147 lines
4.0 KiB
Go

package geojson
import "github.com/tidwall/tile38/geojson/geohash"
// LineString is a geojson object with the type "LineString"
type LineString struct {
Coordinates []Position
BBox *BBox
bboxDefined bool
}
func fillLineString(coordinates []Position, bbox *BBox, err error) (LineString, error) {
if err == nil {
if len(coordinates) < 2 {
err = errLineStringInvalidCoordinates
}
}
bboxDefined := bbox != nil
if !bboxDefined {
cbbox := level2CalculatedBBox(coordinates, nil)
bbox = &cbbox
}
return LineString{
Coordinates: coordinates,
BBox: bbox,
bboxDefined: bboxDefined,
}, err
}
// CalculatedBBox is exterior bbox containing the object.
func (g LineString) CalculatedBBox() BBox {
return level2CalculatedBBox(g.Coordinates, g.BBox)
}
// CalculatedPoint is a point representation of the object.
func (g LineString) CalculatedPoint() Position {
return g.CalculatedBBox().center()
}
// Geohash converts the object to a geohash value.
func (g LineString) Geohash(precision int) (string, error) {
p := g.CalculatedPoint()
return geohash.Encode(p.Y, p.X, precision)
}
// PositionCount return the number of coordinates.
func (g LineString) PositionCount() int {
return level2PositionCount(g.Coordinates, g.BBox)
}
// Weight returns the in-memory size of the object.
func (g LineString) Weight() int {
return level2Weight(g.Coordinates, g.BBox)
}
func (g LineString) appendJSON(json []byte) []byte {
return appendLevel2JSON(json, "LineString", g.Coordinates, g.BBox, g.bboxDefined)
}
// MarshalJSON allows the object to be encoded in json.Marshal calls.
func (g LineString) MarshalJSON() ([]byte, error) {
return g.appendJSON(nil), nil
}
// JSON is the json representation of the object. This might not be exactly the same as the original.
func (g LineString) JSON() string {
return string(g.appendJSON(nil))
}
// String returns a string representation of the object. This might be JSON or something else.
func (g LineString) String() string {
return g.JSON()
}
func (g LineString) bboxPtr() *BBox {
return g.BBox
}
func (g LineString) hasPositions() bool {
return g.bboxDefined || len(g.Coordinates) > 0
}
// WithinBBox detects if the object is fully contained inside a bbox.
func (g LineString) WithinBBox(bbox BBox) bool {
if g.bboxDefined {
return rectBBox(g.CalculatedBBox()).InsideRect(rectBBox(bbox))
}
return polyPositions(g.Coordinates).InsideRect(rectBBox(bbox))
}
// IntersectsBBox detects if the object intersects a bbox.
func (g LineString) IntersectsBBox(bbox BBox) bool {
if g.bboxDefined {
return rectBBox(g.CalculatedBBox()).IntersectsRect(rectBBox(bbox))
}
return polyPositions(g.Coordinates).IntersectsRect(rectBBox(bbox))
}
// Within detects if the object is fully contained inside another object.
func (g LineString) Within(o Object) bool {
return withinObjectShared(g, o,
func(v Polygon) bool {
return polyPositions(g.Coordinates).Inside(polyExteriorHoles(v.Coordinates))
},
func(v MultiPolygon) bool {
for _, c := range v.Coordinates {
if !polyPositions(g.Coordinates).Inside(polyExteriorHoles(c)) {
return false
}
}
return true
},
)
}
// Intersects detects if the object intersects another object.
func (g LineString) Intersects(o Object) bool {
return intersectsObjectShared(g, o,
func(v Polygon) bool {
return polyPositions(g.Coordinates).LineStringIntersects(polyExteriorHoles(v.Coordinates))
},
func(v MultiPolygon) bool {
for _, c := range v.Coordinates {
if polyPositions(g.Coordinates).LineStringIntersects(polyExteriorHoles(c)) {
return true
}
}
return false
},
)
}
// Nearby detects if the object is nearby a position.
func (g LineString) Nearby(center Position, meters float64) bool {
return nearbyObjectShared(g, center.X, center.Y, meters)
}
// IsBBoxDefined returns true if the object has a defined bbox.
func (g LineString) IsBBoxDefined() bool {
return g.bboxDefined
}
// IsGeometry return true if the object is a geojson geometry object. false if it something else.
func (g LineString) IsGeometry() bool {
return true
}