geos

package module
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 Go to latest Published: Aug 3, 2026 License: MIT Imports: 10 Imported by: 31

README

go-geos

PkgGoDev

Package go-geos provides an interface to GEOS.

Install

$ go get github.com/twpayne/go-geos

You must also install the GEOS development headers and libraries. These are typically in the package libgeos-dev on Debian-like systems, geos-devel on RedHat-like systems, and geos in Homebrew.

Features

  • Fluent Go API.

  • Low-level Context, CoordSeq, Geom, PrepGeom, and STRtree types provide access to all GEOS methods.

  • High-level geometry.Geometry type implements all GEOS functionality and many standard Go interfaces:

    • database/sql/driver.Valuer and database/sql.Scanner (WKB) for PostGIS database integration.
    • encoding/json.Marshaler and encoding/json.Unmarshaler (GeoJSON).
    • encoding/xml.Marshaler (KML).
    • encoding.BinaryMarshaler and encoding.BinaryUnmarshaler (WKB).
    • encoding.TextMarshaler and encoding.TextUnmarshaler (WKT).
    • encoding/gob.GobEncoder and encoding/gob.GobDecoder (GOB).

    See the PostGIS example for a demonstration of the use of these interfaces.

  • Concurrency-safe. go-geos uses GEOS's threadsafe *_r functions under the hood, with locking to ensure safety, even when used across multiple goroutines. For best performance, use one geos.Context per goroutine.

  • Caching of geometry properties to avoid cgo overhead.

  • Optimized GeoJSON encoder.

  • Automatic cleanup of GEOS objects.

Memory management

go-geos objects live mostly on the C heap. go-geos sets cleanup functions on the objects it creates that free the associated C memory. However, the C heap is not visible to the Go runtime. The can result in significant memory pressure as memory is consumed by large, un-freed geometries, of which the Go runtime is unaware.

Ownership

Returned sub-geometries (e.g. polygon rings or geometries in a collection) and coordinate sequences are owned by the geometry and will keep the geometry alive with a reference to it. Collections take ownership of all their geometries: directly if the geometry is unowned, or via cloning for an already-owned geometry.

Errors, exceptions, and panics

go-geos uses the stable GEOS C bindings. These bindings catch exceptions from the underlying C++ code and convert them to an integer return code. For normal geometry operations, go-geos panics whenever it encounters a GEOS return code indicating an error, rather than returning an error. Such panics will not occur if go-geos is used correctly. Panics will occur for invalid API calls, out-of-bounds access, or operations on invalid geometries. This behavior is similar to slice access in Go (out-of-bounds accesses panic) and keeps the API fluent. When parsing data, errors are expected so an error is returned.

Comparison with github.com/twpayne/go-geom

github.com/twpayne/go-geom is a pure Go library providing similar functionality to go-geos. The major differences are:

  • go-geos uses GEOS, which is an extremely mature library with a rich feature set.
  • go-geos uses cgo, with all the disadvantages that that entails, notably expensive function call overhead, more complex memory management and trickier cross-compilation.
  • go-geom uses a cache-friendly coordinate layout which is generally faster than GEOS for many operations.

go-geos is a good fit if your program is short-lived (meaning you can ignore memory management), or you require the battle-tested geometry functions provided by GEOS and are willing to handle memory management manually. go-geom is recommended for long-running processes with less stringent geometry function requirements.

GEOS version compatibility

go-geos is tested to work with the versions of GEOS tested on CI. See here.

Calling functions unsupported by the underlying GEOS library will result in a panic. Users can use VersionCompare to be sure that a function exists.

Contributing

Please check CONTRIBUTING.md for instructions before you open a pull-request!

License

MIT

Documentation

Overview

Package geos provides an interface to GEOS. See https://trac.osgeo.org/geos/.

Index

Examples

Constants

View Source 
const (
	VersionMajor = C.GEOS_VERSION_MAJOR
	VersionMinor = C.GEOS_VERSION_MINOR
	VersionPatch = C.GEOS_VERSION_PATCH
)

Version.

Variables

View Source 
var DefaultContext = NewContext()

DefaultContext is the default context.

Functions

func VersionCompare added in v0.15.0 

func VersionCompare(major, minor, patch int) int

VersionCompare returns a negative number if the GEOS version is less than the given major.minor.patch version, zero if it is equal, or a positive number otherwise.

Types

type Box2D added in v0.17.0 

type Box2D struct {
	MinX float64
	MinY float64
	MaxX float64
	MaxY float64
}

A Box2D is a two-dimensional bounds.

func NewBox2D added in v0.17.0 

func NewBox2D(minX, minY, maxX, maxY float64) *Box2D

NewBox2D returns a new bounds.

func NewBox2DEmpty added in v0.17.0 

func NewBox2DEmpty() *Box2D

NewBox2DEmpty returns a new empty bounds.

func (*Box2D) Contains added in v0.17.0 

func (b *Box2D) Contains(other *Box2D) bool

Contains returns true if b contains other.

func (*Box2D) ContainsPoint added in v0.17.0 

func (b *Box2D) ContainsPoint(x, y float64) bool

ContainsPoint returns true if b contains the point at x, y.

func (*Box2D) ContextGeom added in v0.17.0 

func (b *Box2D) ContextGeom(context *Context) *Geom

ContextGeom returns b as a Geom.

func (*Box2D) Equals added in v0.17.0 

func (b *Box2D) Equals(other *Box2D) bool

Equals returns true if b equals other.

func (*Box2D) Geom added in v0.17.0 

func (b *Box2D) Geom() *Geom

Geom returns b as a Geom.

func (*Box2D) Height added in v0.17.0 

func (b *Box2D) Height() float64

Height returns the height of b.

func (*Box2D) Intersects added in v0.17.0 

func (b *Box2D) Intersects(other *Box2D) bool

Intersects returns true if b intersects other.

func (*Box2D) IsEmpty added in v0.17.0 

func (b *Box2D) IsEmpty() bool

IsEmpty returns true if b is empty.

func (*Box2D) IsPoint added in v0.17.0 

func (b *Box2D) IsPoint() bool

IsPoint returns true if b is a point.

func (*Box2D) String added in v0.17.0 

func (b *Box2D) String() string

func (*Box2D) Width added in v0.17.0 

func (b *Box2D) Width() float64

Width returns the width of b.

type Box3D added in v0.18.0 

type Box3D struct {
	MinX float64
	MinY float64
	MinZ float64
	MaxX float64
	MaxY float64
	MaxZ float64
}

A Box3D is a three-dimensional bounds.

func NewBox3D added in v0.18.0 

func NewBox3D(minX, minY, minZ, maxX, maxY, maxZ float64) *Box3D

NewBox3D returns a new bounds.

func NewBox3DEmpty added in v0.18.0 

func NewBox3DEmpty() *Box3D

NewBox3DEmpty returns a new empty bounds.

func (*Box3D) String added in v0.18.0 

func (b *Box3D) String() string

type BufCapStyle added in v0.7.0 

type BufCapStyle int
const (
	BufCapStyleRound  BufCapStyle = C.GEOSBUF_CAP_ROUND
	BufCapStyleFlat   BufCapStyle = C.GEOSBUF_CAP_FLAT
	BufCapStyleSquare BufCapStyle = C.GEOSBUF_CAP_SQUARE
)

Buffer cap styles.

type BufJoinStyle added in v0.7.0 

type BufJoinStyle int
const (
	BufJoinStyleRound BufJoinStyle = C.GEOSBUF_JOIN_ROUND
	BufJoinStyleMitre BufJoinStyle = C.GEOSBUF_JOIN_MITRE
	BufJoinStyleBevel BufJoinStyle = C.GEOSBUF_JOIN_BEVEL
)

Buffer join styles.

type BufParams added in v0.20.2 

type BufParams struct {
	// contains filtered or unexported fields
}

A BufParams contains parameters for BufferWithParams.

func (*BufParams) SetEndCapStyle added in v0.20.2 

func (p *BufParams) SetEndCapStyle(style BufCapStyle) *BufParams

SetEndCapStyle sets p's end cap style.

func (*BufParams) SetJoinStyle added in v0.20.2 

func (p *BufParams) SetJoinStyle(style BufJoinStyle) *BufParams

SetJoinStyle sets p's join style.

func (*BufParams) SetMitreLimit added in v0.20.2 

func (p *BufParams) SetMitreLimit(mitreLimit float64) *BufParams

SetMitreLimit sets p's mitre limit.

func (*BufParams) SetQuadrantSegments added in v0.20.2 

func (p *BufParams) SetQuadrantSegments(quadSegs int) *BufParams

SetQuadrantSegments sets the number of segments to stroke each quadrant of circular arcs.

func (*BufParams) SetSingleSided added in v0.20.2 

func (p *BufParams) SetSingleSided(singleSided bool) *BufParams

SetSingleSided sets whether the computed buffer should be single sided.

type Context 

type Context struct {
	// contains filtered or unexported fields
}

A Context is a context.

func NewContext 

func NewContext() *Context

NewContext returns a new Context.

func (*Context) Clone 

func (c *Context) Clone(g *Geom) *Geom

Clone clones g into c.

func (*Context) NewBufParams added in v0.20.2 

func (c *Context) NewBufParams() *BufParams

NewBufParams returns a new BufParams.

func (*Context) NewCollection 

func (c *Context) NewCollection(typeID TypeID, geoms []*Geom) *Geom

NewCollection returns a new collection which owns all the supplied geometries; either directly if they were un-owned, or via clones if they were owned already.

func (*Context) NewCoordSeq 

func (c *Context) NewCoordSeq(size, dims int) *CoordSeq

NewCoordSeq returns a new CoordSeq.

func (*Context) NewCoordSeqFromCoords 

func (c *Context) NewCoordSeqFromCoords(coords [][]float64) *CoordSeq

NewCoordSeqFromCoords returns a new CoordSeq populated with coords.

func (*Context) NewEmptyCollection 

func (c *Context) NewEmptyCollection(typeID TypeID) *Geom

NewEmptyCollection returns a new empty collection.

func (*Context) NewEmptyLineString 

func (c *Context) NewEmptyLineString() *Geom

NewEmptyLineString returns a new empty line string.

func (*Context) NewEmptyPoint 

func (c *Context) NewEmptyPoint() *Geom

NewEmptyPoint returns a new empty point.

func (*Context) NewEmptyPolygon 

func (c *Context) NewEmptyPolygon() *Geom

NewEmptyPolygon returns a new empty polygon.

func (*Context) NewGeoJSONReader added in v0.20.2 

func (c *Context) NewGeoJSONReader() *GeoJSONReader

NewGeoJSONReader returns a new GeoJSONReader.

func (*Context) NewGeoJSONWriter added in v0.20.2 

func (c *Context) NewGeoJSONWriter() *GeoJSONWriter

NewGeoJSONWriter returns a new GeoJSONWriter.

func (*Context) NewGeomFromBounds 

func (c *Context) NewGeomFromBounds(minX, minY, maxX, maxY float64) *Geom

NewGeomFromBounds returns a new polygon constructed from bounds.

func (*Context) NewGeomFromGeoJSON added in v0.4.0 

func (c *Context) NewGeomFromGeoJSON(geoJSON string) (*Geom, error)

NewGeomFromGeoJSON returns a new geometry in JSON format from json.

func (*Context) NewGeomFromWKB 

func (c *Context) NewGeomFromWKB(wkb []byte) (*Geom, error)

NewGeomFromWKB parses a geometry in WKB format from wkb.

func (*Context) NewGeomFromWKT 

func (c *Context) NewGeomFromWKT(wkt string) (*Geom, error)

NewGeomFromWKT parses a geometry in WKT format from wkt.

func (*Context) NewLineString 

func (c *Context) NewLineString(coords [][]float64) *Geom

NewLineString returns a new line string populated with coords.

func (*Context) NewLinearRing 

func (c *Context) NewLinearRing(coords [][]float64) *Geom

NewLinearRing returns a new linear ring populated with coords.

func (*Context) NewPoint 

func (c *Context) NewPoint(coord []float64) *Geom

NewPoint returns a new point populated with coord.

func (*Context) NewPointFromXY added in v0.13.0 

func (c *Context) NewPointFromXY(x, y float64) *Geom

NewPointFromXY returns a new point with a x and y.

func (*Context) NewPoints added in v0.3.0 

func (c *Context) NewPoints(coords [][]float64) []*Geom

NewPoints returns a new slice of points populated from coords.

func (*Context) NewPolygon 

func (c *Context) NewPolygon(coordss [][][]float64) *Geom

NewPolygon returns a new polygon populated with coordss.

func (*Context) NewSTRtree added in v0.12.0 

func (c *Context) NewSTRtree(nodeCapacity int) *STRtree

NewSTRtree returns a new STRtree.

func (*Context) NewWKBReader added in v0.20.2 

func (c *Context) NewWKBReader() *WKBReader

NewWKBReader returns a new WKBReader.

func (*Context) NewWKBWriter added in v0.20.2 

func (c *Context) NewWKBWriter(options ...WKBWriterOption) *WKBWriter

NewWKBWriter returns a new WKBWriter with the given options.

func (*Context) NewWKTReader added in v0.20.2 

func (c *Context) NewWKTReader() *WKTReader

NewWKTReader returns a new WKTReader.

func (*Context) NewWKTWriter added in v0.20.2 

func (c *Context) NewWKTWriter() *WKTWriter

NewWKTWriter returns a new WKTWriter.

func (*Context) OrientationIndex added in v0.13.0 

func (c *Context) OrientationIndex(ax, ay, bx, by, px, py float64) int

OrientationIndex returns the orientation index from A to B and then to P.

func (*Context) Polygonize added in v0.9.0 

func (c *Context) Polygonize(geoms []*Geom) *Geom

Polygonize returns a set of geometries which contains linework that represents the edges of a planar graph.

func (*Context) PolygonizeValid added in v0.9.0 

func (c *Context) PolygonizeValid(geoms []*Geom) *Geom

PolygonizeValid returns a set of polygons which contains linework that represents the edges of a planar graph.

func (*Context) RelatePatternMatch added in v0.12.0 

func (c *Context) RelatePatternMatch(mat, pat string) bool

RelatePatternMatch returns if two DE9IM patterns are consistent.

func (*Context) SegmentIntersection added in v0.12.0 

func (c *Context) SegmentIntersection(ax0, ay0, ax1, ay1, bx0, by0, bx1, by1 float64) (x, y float64, intersection bool)

SegmentIntersection returns the coordinate where two lines intersect.

type CoordSeq 

type CoordSeq struct {
	// contains filtered or unexported fields
}

A CoordSeq is a coordinate sequence.

func NewCoordSeq 

func NewCoordSeq(size, dims int) *CoordSeq

NewCoordSeq returns a new CoordSeq.

func NewCoordSeqFromCoords 

func NewCoordSeqFromCoords(coords [][]float64) *CoordSeq

NewCoordSeqFromCoords returns a new CoordSeq populated with coords.

func (*CoordSeq) Clone 

func (s *CoordSeq) Clone() *CoordSeq

Clone returns a clone of s.

func (*CoordSeq) Dimensions 

func (s *CoordSeq) Dimensions() int

Dimensions returns the dimensions of s.

func (*CoordSeq) IsCCW added in v0.10.0 

func (s *CoordSeq) IsCCW() bool

IsCCW returns if s is counter-clockwise.

func (*CoordSeq) Ordinate 

func (s *CoordSeq) Ordinate(idx, dim int) float64

Ordinate returns the idx-th dim coordinate of s.

func (*CoordSeq) SetOrdinate 

func (s *CoordSeq) SetOrdinate(idx, dim int, val float64)

SetOrdinate sets the idx-th dim coordinate of s to val.

func (*CoordSeq) SetX 

func (s *CoordSeq) SetX(idx int, val float64)

SetX sets the idx-th X coordinate of s to val.

func (*CoordSeq) SetY 

func (s *CoordSeq) SetY(idx int, val float64)

SetY sets the idx-th Y coordinate of s to val.

func (*CoordSeq) SetZ 

func (s *CoordSeq) SetZ(idx int, val float64)

SetZ sets the idx-th Z coordinate of s to val.

func (*CoordSeq) Size 

func (s *CoordSeq) Size() int

Size returns the size of s.

func (*CoordSeq) ToCoords 

func (s *CoordSeq) ToCoords() [][]float64

ToCoords returns s as a [][]float64.

func (*CoordSeq) X 

func (s *CoordSeq) X(idx int) float64

X returns the idx-th X coordinate of s.

func (*CoordSeq) Y 

func (s *CoordSeq) Y(idx int) float64

Y returns the idx-th Y coordinate of s.

func (*CoordSeq) Z 

func (s *CoordSeq) Z(idx int) float64

Z returns the idx-th Z coordinate of s.

type Error 

type Error string

An Error is an error returned by GEOS.

func (Error) Error 

func (e Error) Error() string

type GeoJSONReader added in v0.20.2 

type GeoJSONReader struct {
	// contains filtered or unexported fields
}

A GeoJSONReader reads GeoJSON.

func (*GeoJSONReader) ReadGeometry added in v0.20.2 

func (r *GeoJSONReader) ReadGeometry(geoJSON string) (*Geom, error)

ReadGeometry reads a geometry from geoJSON.

type GeoJSONWriter added in v0.20.2 

type GeoJSONWriter struct {
	// contains filtered or unexported fields
}

A GeoJSONWriter writes geometries as GeoJSON.

func (*GeoJSONWriter) WriteGeometry added in v0.20.2 

func (w *GeoJSONWriter) WriteGeometry(g *Geom, indent int) string

WriteGeometry returns the GeoJSON representation of g.

type Geom 

type Geom struct {
	// contains filtered or unexported fields
}

A Geom is a geometry.

func Clone 

func Clone(g *Geom) *Geom

Clone clones g into c.

func NewCollection 

func NewCollection(typeID TypeID, geoms []*Geom) *Geom

NewCollection returns a new collection.

func NewEmptyCollection 

func NewEmptyCollection(typeID TypeID) *Geom

NewEmptyCollection returns a new empty collection.

func NewEmptyLineString 

func NewEmptyLineString() *Geom

NewEmptyLineString returns a new empty line string.

func NewEmptyPoint 

func NewEmptyPoint() *Geom

NewEmptyPoint returns a new empty point.

func NewEmptyPolygon 

func NewEmptyPolygon() *Geom

NewEmptyPolygon returns a new empty polygon.

func NewGeomFromBounds 

func NewGeomFromBounds(minX, minY, maxX, maxY float64) *Geom

NewGeomFromBounds returns a new polygon populated with bounds.

func NewGeomFromGeoJSON added in v0.4.0 

func NewGeomFromGeoJSON(geoJSON string) (*Geom, error)

NewGeomFromGeoJSON parses a geometry in GeoJSON format from GeoJSON.

func NewGeomFromWKB 

func NewGeomFromWKB(wkb []byte) (*Geom, error)

NewGeomFromWKB parses a geometry in WKB format from wkb.

func NewGeomFromWKT 

func NewGeomFromWKT(wkt string) (*Geom, error)

NewGeomFromWKT parses a geometry in WKT format from wkt.

func NewLineString 

func NewLineString(coords [][]float64) *Geom

NewLineString returns a new line string populated with coords.

func NewLinearRing 

func NewLinearRing(coords [][]float64) *Geom

NewLinearRing returns a new linear ring populated with coords.

func NewPoint 

func NewPoint(coord []float64) *Geom

NewPoint returns a new point populated with coord.

func NewPointFromXY added in v0.13.0 

func NewPointFromXY(x, y float64) *Geom

NewPointFromXY returns a new point with x and y.

func NewPolygon 

func NewPolygon(coordss [][][]float64) *Geom

NewPolygon returns a new polygon populated with coordss.

func Polygonize added in v0.9.0 

func Polygonize(geoms []*Geom) *Geom

Polygonize returns a set of geometries which contains linework that represents the edges of a planar graph.

func PolygonizeValid added in v0.9.0 

func PolygonizeValid(geoms []*Geom) *Geom

PolygonizeValid returns a set of polygons which contains linework that represents the edges of a planar graph.

func (*Geom) Area added in v0.4.0 

func (g *Geom) Area() float64

Area returns g's area.

func (*Geom) Boundary added in v0.13.0 

func (g *Geom) Boundary() *Geom

Boundary returns the boundary of g.

func (*Geom) Bounds 

func (g *Geom) Bounds() *Box2D

Bounds returns g's bounds.

func (*Geom) Buffer added in v0.4.0 

func (g *Geom) Buffer(width float64, quadsegs int) *Geom

Buffer returns g with the given buffer.

func (*Geom) BufferWithParams added in v0.17.0 

func (g *Geom) BufferWithParams(bufParams *BufParams, width float64) *Geom

BufferWithParams returns g buffered with bufParams.

func (*Geom) BufferWithStyle added in v0.7.0 

func (g *Geom) BufferWithStyle(width float64, quadsegs int, endCapStyle BufCapStyle, joinStyle BufJoinStyle, mitreLimit float64) *Geom

BufferWithStyle returns a buffer using the provided style parameters.

func (*Geom) BuildArea added in v0.10.0 

func (g *Geom) BuildArea() *Geom

BuildArea returns the polygonization using all the linework, assuming that rings contained within rings are empty holes, rather than extra PolygonHoleSimplify.

func (*Geom) Centroid added in v0.13.0 

func (g *Geom) Centroid() *Geom

Centroid returns a point at the center of mass of g.

func (*Geom) ClipByBox2D added in v0.17.0 

func (g *Geom) ClipByBox2D(box2d *Box2D) *Geom

ClipByBox2D clips g by box2d.

func (*Geom) ClipByRect added in v0.10.0 

func (g *Geom) ClipByRect(minX float64, minY float64, maxX float64, maxY float64) *Geom

ClipByRect returns g clipped to a rectangular polygon.

func (*Geom) Clone 

func (g *Geom) Clone() *Geom

Clone returns a clone of g.

func (*Geom) ConcaveHull added in v0.7.0 

func (g *Geom) ConcaveHull(ratio float64, allowHoles uint) *Geom

ConcaveHull returns the concave hull of g.

func (*Geom) ConcaveHullByLength added in v0.14.0 

func (g *Geom) ConcaveHullByLength(ratio float64, allowHoles uint) *Geom

ConcaveHullByLength returns the concave hull of g.

func (*Geom) ConstrainedDelaunayTriangulation added in v0.13.0 

func (g *Geom) ConstrainedDelaunayTriangulation() *Geom

ConstrainedDelaunayTriangulation returns the constrained Delaunay triangulation of the vertices of the g.

func (*Geom) Contains 

func (g *Geom) Contains(other *Geom) bool

Contains returns true if g contains other.

func (*Geom) ConvexHull 

func (g *Geom) ConvexHull() *Geom

ConvexHull returns g's convex hull.

func (*Geom) CoordSeq 

func (g *Geom) CoordSeq() *CoordSeq

CoordSeq returns g's coordinate sequence. The returned CoordSeq is owned by g and will keep it alive.

func (*Geom) CoverageUnion added in v0.10.0 

func (g *Geom) CoverageUnion() *Geom

CoverageUnion returns the union of g for polygonal inputs that are correctly noded and do not overlap.

func (*Geom) CoveredBy 

func (g *Geom) CoveredBy(other *Geom) bool

CoveredBy returns true if g is covered by other.

func (*Geom) Covers 

func (g *Geom) Covers(other *Geom) bool

Covers returns true if g covers other.

func (*Geom) Crosses 

func (g *Geom) Crosses(other *Geom) bool

Crosses returns true if g crosses other.

func (*Geom) Densify added in v0.4.0 

func (g *Geom) Densify(tolerance float64) *Geom

Densify returns g densified with the given tolerance.

func (*Geom) Difference added in v0.6.0 

func (g *Geom) Difference(other *Geom) *Geom

Difference returns the difference between g and other.

func (*Geom) DifferencePrec added in v0.6.0 

func (g *Geom) DifferencePrec(other *Geom, gridSize float64) *Geom

DifferencePrec returns the difference between g and other.

func (*Geom) Disjoint 

func (g *Geom) Disjoint(other *Geom) bool

Disjoint returns true if g is disjoint from other.

func (*Geom) DisjointSubsetUnion added in v0.20.1 

func (g *Geom) DisjointSubsetUnion() *Geom

DisjointSubsetUnion returns the union of all components of a single geometry (optimized for inputs that can be divided into subsets that do not intersect).

func (*Geom) Distance added in v0.3.0 

func (g *Geom) Distance(other *Geom) float64

Distance returns the distance between the closes points on g and other.

func (*Geom) DistanceIndexed added in v0.5.0 

func (g *Geom) DistanceIndexed(other *Geom) float64

DistanceIndexed returns the distance between g and other, using the indexed facet distance.

func (*Geom) DistanceWithin added in v0.5.0 

func (g *Geom) DistanceWithin(other *Geom, dist float64) bool

DistanceWithin returns whether the distance between g and other is within the given dist.

func (*Geom) EndPoint added in v0.13.0 

func (g *Geom) EndPoint() *Geom

EndPoint returns the last point of a LineString.

func (*Geom) Envelope 

func (g *Geom) Envelope() *Geom

Envelope returns the envelope of g.

func (*Geom) Equals 

func (g *Geom) Equals(other *Geom) bool

Equals returns true if g equals other.

func (*Geom) EqualsExact 

func (g *Geom) EqualsExact(other *Geom, tolerance float64) bool

EqualsExact returns true if g equals other exactly.

func (*Geom) ExteriorRing 

func (g *Geom) ExteriorRing() *Geom

ExteriorRing returns the exterior ring. The returned geometry is a sub-geometry of g and will keep it alive.

func (*Geom) FrechetDistance added in v0.5.0 

func (g *Geom) FrechetDistance(other *Geom) float64

FrechetDistance returns the Fréchet distance between g and other.

func (*Geom) FrechetDistanceDensify added in v0.5.0 

func (g *Geom) FrechetDistanceDensify(other *Geom, densifyFrac float64) float64

FrechetDistanceDensify returns the Fréchet distance between g and other.

func (*Geom) Geometry 

func (g *Geom) Geometry(n int) *Geom

Geometry returns the nth geometry of g. The returned geometry is a sub-geometry of g and will keep it alive.

func (*Geom) HasZ added in v0.10.0 

func (g *Geom) HasZ() bool

HasZ returns if g has Z coordinates.

func (*Geom) HausdorffDistance added in v0.5.0 

func (g *Geom) HausdorffDistance(other *Geom) float64

HausdorffDistance returns the Hausdorff distance between g and other.

func (*Geom) HausdorffDistanceDensify added in v0.5.0 

func (g *Geom) HausdorffDistanceDensify(other *Geom, densifyFrac float64) float64

HausdorffDistanceDensify returns the Hausdorff distance between g and other.

func (*Geom) InteriorRing 

func (g *Geom) InteriorRing(n int) *Geom

InteriorRing returns the nth interior ring. The returned geometry is a sub-geometry of g and will keep it alive.

func (*Geom) Interpolate added in v0.7.0 

func (g *Geom) Interpolate(d float64) *Geom

Interpolate returns a point distance d from the start of g, which must be a linestring.

func (*Geom) InterpolateNormalized added in v0.7.0 

func (g *Geom) InterpolateNormalized(proportion float64) *Geom

InterpolateNormalized returns the point that is at proportion from the start.

func (*Geom) Intersection 

func (g *Geom) Intersection(other *Geom) *Geom

Intersection returns the intersection of g and other.

func (*Geom) IntersectionPrec added in v0.7.0 

func (g *Geom) IntersectionPrec(other *Geom, gridSize float64) *Geom

IntersectionPrec returns the intersection of g and other.

func (*Geom) Intersects 

func (g *Geom) Intersects(other *Geom) bool

Intersects returns true if g intersects other.

func (*Geom) IsClosed 

func (g *Geom) IsClosed() bool

IsClosed returns true if g is closed.

func (*Geom) IsEmpty 

func (g *Geom) IsEmpty() bool

IsEmpty returns true if g is empty.

func (*Geom) IsRing 

func (g *Geom) IsRing() bool

IsRing returns true if g is a ring.

func (*Geom) IsSimple 

func (g *Geom) IsSimple() bool

IsSimple returns true if g is simple.

func (*Geom) IsValid 

func (g *Geom) IsValid() bool

IsValid returns true if g is valid.

func (*Geom) IsValidReason 

func (g *Geom) IsValidReason() string

IsValidReason returns the reason that g is invalid.

func (*Geom) LargestEmptyCircle added in v0.13.0 

func (g *Geom) LargestEmptyCircle(other *Geom, tolerance float64) *Geom

LargestEmptyCircle returns the largest empty circle for g, up to a specified tolerance.

func (*Geom) Length added in v0.4.0 

func (g *Geom) Length() float64

Length returns g's length.

func (*Geom) LineMerge added in v0.13.0 

func (g *Geom) LineMerge() *Geom

LineMerge returns a set of fully noded LineStrings, removing any cardinality 2 nodes in the linework.

func (*Geom) MakeValid added in v0.8.0 

func (g *Geom) MakeValid() *Geom

MakeValid repairs an invalid geometry, returning a valid output.

func (*Geom) MakeValidWithParams added in v0.14.0 

func (g *Geom) MakeValidWithParams(method MakeValidMethod, collapse MakeValidCollapsed) *Geom

MakeValidWithParams returns a new valid geometry using the MakeValidMethods and MakeValidCollapsed parameters.

func (*Geom) MaximumInscribedCircle added in v0.7.0 

func (g *Geom) MaximumInscribedCircle(tolerance float64) *Geom

MaximumInscribedCircle returns the maximum inscribed circle of g up to the the given tolerance.

func (*Geom) MinimumClearance added in v0.13.0 

func (g *Geom) MinimumClearance() float64

MinimumClearance returns the minimum clearance of g.

func (*Geom) MinimumClearanceLine added in v0.13.0 

func (g *Geom) MinimumClearanceLine() *Geom

MinimumClearanceLine returns a LineString whose endpoints define the minimum clearance of g.

func (*Geom) MinimumRotatedRectangle added in v0.7.0 

func (g *Geom) MinimumRotatedRectangle() *Geom

MinimumRotatedRectangle returns the minimum rotated rectangle enclosing g.

func (*Geom) MinimumWidth added in v0.4.0 

func (g *Geom) MinimumWidth() *Geom

MinimumWidth returns a linestring geometry which represents the minimum diameter of g.

func (*Geom) NearestPoints added in v0.3.0 

func (g *Geom) NearestPoints(other *Geom) [][]float64

NearestPoints returns the nearest coordinates of g and other. If the nearest coordinates do not exist (e.g., when either geom is empty), it returns nil.

func (*Geom) Node added in v0.10.0 

func (g *Geom) Node() *Geom

Node returns a new geometry in which no lines cross each other, and all touching occurs at endpoints.

func (*Geom) Normalize added in v0.10.0 

func (g *Geom) Normalize() *Geom

func (*Geom) NumCoordinates added in v0.13.0 

func (g *Geom) NumCoordinates() int

NumCoordinates returns the number of coordinates in g.

func (*Geom) NumGeometries 

func (g *Geom) NumGeometries() int

NumGeometries returns the number of geometries in g.

func (*Geom) NumInteriorRings 

func (g *Geom) NumInteriorRings() int

NumInteriorRings returns the number of interior rings in g.

func (*Geom) NumPoints 

func (g *Geom) NumPoints() int

NumPoints returns the number of points in g.

func (*Geom) OffsetCurve added in v0.7.0 

func (g *Geom) OffsetCurve(width float64, quadsegs int, joinStyle BufJoinStyle, mitreLimit float64) *Geom

OffsetCurve returns the offset curve line(s) of g.

func (*Geom) Overlaps 

func (g *Geom) Overlaps(other *Geom) bool

Overlaps returns true if g overlaps other.

func (*Geom) Point 

func (g *Geom) Point(n int) *Geom

Point returns the g's nth point.

func (*Geom) PointOnSurface added in v0.13.0 

func (g *Geom) PointOnSurface() *Geom

PointOnSurface returns a point that is inside the boundary of a polygonal geometry.

func (*Geom) PolygonizeFull added in v0.9.0 

func (g *Geom) PolygonizeFull() (geom, cuts, dangles, invalidRings *Geom)

PolygonizeFull returns a set of geometries which contains linework that represents the edge of a planar graph.

func (*Geom) Precision added in v0.10.0 

func (g *Geom) Precision() float64

Precision returns g's precision.

func (*Geom) Prepare 

func (g *Geom) Prepare() *PrepGeom

Prepare prepares g.

func (*Geom) Project added in v0.11.0 

func (g *Geom) Project(other *Geom) float64

Project returns the distance of other(a point) projected onto g(a line) from the start of the line.

func (*Geom) ProjectNormalized added in v0.11.0 

func (g *Geom) ProjectNormalized(other *Geom) float64

ProjectNormalized returns the proportional distance of other(a point) projected onto g(a line) from the start of the line. For example, a point that projects to the middle of a line would be return 0.5.

func (*Geom) Relate added in v0.12.0 

func (g *Geom) Relate(other *Geom) string

Relate returns the DE9IM pattern for g and other.

func (*Geom) RelateBoundaryNodeRule added in v0.12.0 

func (g *Geom) RelateBoundaryNodeRule(other *Geom, bnr RelateBoundaryNodeRule) string

RelateBoundaryNodeRule returns the DE9IM pattern for g and other.

func (*Geom) RelatePattern added in v0.12.0 

func (g *Geom) RelatePattern(other *Geom, pat string) bool

RelatePattern returns if the DE9IM pattern for g and other matches pat.

func (*Geom) ReleaseCollection added in v0.22.0 

func (g *Geom) ReleaseCollection() []*Geom

ReleaseCollection removes and returns all the geometries from the collection g.

func (*Geom) Reverse added in v0.12.0 

func (g *Geom) Reverse() *Geom

Reverse returns g with sequence orders reversed.

func (*Geom) SRID 

func (g *Geom) SRID() int

SRID returns g's SRID.

func (*Geom) SetPrecision added in v0.8.0 

func (g *Geom) SetPrecision(gridSize float64, flags PrecisionRule) *Geom

SetPrecision changes the coordinate precision of g.

func (*Geom) SetSRID 

func (g *Geom) SetSRID(srid int) *Geom

SetSRID sets g's SRID to srid.

func (*Geom) SetUserData added in v0.10.0 

func (g *Geom) SetUserData(userdata uintptr) *Geom

SetUserData sets g's userdata and returns g.

func (*Geom) SharedPaths added in v0.10.0 

func (g *Geom) SharedPaths(other *Geom) *Geom

SharedPaths returns the paths shared between g and other, which must be lineal geometries.

func (*Geom) Simplify added in v0.8.0 

func (g *Geom) Simplify(tolerance float64) *Geom

Simplify returns a simplified geometry.

func (*Geom) Snap added in v0.13.0 

func (g *Geom) Snap(other *Geom, tolerance float64) *Geom

Snap returns a geometry with the vertices and segments of g snapped to other within the given tolerance.

func (*Geom) StartPoint added in v0.13.0 

func (g *Geom) StartPoint() *Geom

StartPoint returns the first point of a LineString.

func (*Geom) String 

func (g *Geom) String() string

String returns g in WKT format.

func (*Geom) SymDifference added in v0.7.0 

func (g *Geom) SymDifference(other *Geom) *Geom

SymDifference returns the symmetric difference between g and other.

func (*Geom) SymDifferencePrec added in v0.10.0 

func (g *Geom) SymDifferencePrec(other *Geom, gridSize float64) *Geom

SymDifferencePrec returns the symmetric difference between g and other.

func (*Geom) ToEWKBWithSRID added in v0.16.0 

func (g *Geom) ToEWKBWithSRID() []byte

ToEWKBWithSRID returns g in Extended WKB format with its SRID.

func (*Geom) ToGeoJSON added in v0.4.0 

func (g *Geom) ToGeoJSON(indent int) string

ToGeoJSON returns g in GeoJSON format.

func (*Geom) ToWKB 

func (g *Geom) ToWKB() []byte

ToWKB returns g in WKB format.

func (*Geom) ToWKT 

func (g *Geom) ToWKT() string

ToWKT returns g in WKT format.

func (*Geom) TopologyPreserveSimplify added in v0.8.0 

func (g *Geom) TopologyPreserveSimplify(tolerance float64) *Geom

TopologyPreserveSimplify returns a simplified geometry preserving topology.

func (*Geom) Touches 

func (g *Geom) Touches(other *Geom) bool

Touches returns true if g touches other.

func (*Geom) Type 

func (g *Geom) Type() string

Type returns g's type.

func (*Geom) TypeID 

func (g *Geom) TypeID() TypeID

TypeID returns g's geometry type id.

func (*Geom) UnaryUnion added in v0.4.0 

func (g *Geom) UnaryUnion() *Geom

UnaryUnion returns the union of all components of a single geometry.

func (*Geom) UnaryUnionPrec added in v0.10.0 

func (g *Geom) UnaryUnionPrec(gridSize float64) *Geom

UnaryUnionPrec returns the union of all components of a single geometry.

func (*Geom) Union added in v0.10.0 

func (g *Geom) Union(other *Geom) *Geom

Union returns the union of g and other.

func (*Geom) UnionPrec added in v0.10.0 

func (g *Geom) UnionPrec(other *Geom, gridSize float64) *Geom

UnionPrec returns the union of g and other.

func (*Geom) UserData added in v0.10.0 

func (g *Geom) UserData() uintptr

UserData returns g's userdata.

func (*Geom) VoronoiDiagram added in v0.21.0 

func (g *Geom) VoronoiDiagram(env *Geom, tolerance float64, flags VoronoiDiagramFlag) *Geom

VoronoiDiagram returns the Voronoi diagram of the vertices of g.

func (*Geom) Within 

func (g *Geom) Within(other *Geom) bool

Within returns true if g is within other.

func (*Geom) X 

func (g *Geom) X() float64

X returns g's X coordinate.

func (*Geom) Y 

func (g *Geom) Y() float64

Y returns g's Y coordinate.

type MakeValidCollapsed added in v0.14.0 

type MakeValidCollapsed int
const (
	MakeValidDiscardCollapsed MakeValidCollapsed = 0
	MakeValidKeepCollapsed    MakeValidCollapsed = C.GEOS_PREC_KEEP_COLLAPSED
)

MakeValidMethods.

type MakeValidMethod added in v0.14.0 

type MakeValidMethod int
const (
	MakeValidLinework  MakeValidMethod = C.GEOS_MAKE_VALID_LINEWORK
	MakeValidStructure MakeValidMethod = C.GEOS_MAKE_VALID_STRUCTURE
)

MakeValidMethods.

type PrecisionRule added in v0.8.0 

type PrecisionRule int
const (
	PrecisionRuleNone          PrecisionRule = 0
	PrecisionRuleValidOutput   PrecisionRule = C.GEOS_PREC_VALID_OUTPUT
	PrecisionRuleNoTopo        PrecisionRule = C.GEOS_PREC_NO_TOPO
	PrecisionRulePointwise     PrecisionRule = C.GEOS_PREC_NO_TOPO
	PrecisionRuleKeepCollapsed PrecisionRule = C.GEOS_PREC_KEEP_COLLAPSED
)

Precision rules.

type PrepGeom 

type PrepGeom struct {
	// contains filtered or unexported fields
}

A PrepGeom is a prepared geometry.

Example 
package main

import (
	"fmt"

	"github.com/twpayne/go-geos"
)

func main() {
	geom, err := geos.NewGeomFromWKT("POLYGON ((189 115, 200 170, 130 170, 35 242, 156 215, 210 290, 274 256, 360 190, 267 215, 300 50, 200 60, 189 115))")
	if err != nil {
		panic(err)
	}
	prepGeom := geom.Prepare()
	point := geos.NewPointFromXY(190, 200)
	if prepGeom.Intersects(point) {
		fmt.Println("intersects")
	}
}

Output:
intersects

func (*PrepGeom) Contains 

func (pg *PrepGeom) Contains(g *Geom) bool

Contains returns if pg contains g.

func (*PrepGeom) ContainsProperly 

func (pg *PrepGeom) ContainsProperly(g *Geom) bool

ContainsProperly returns if pg contains g properly.

func (*PrepGeom) ContainsXY added in v0.19.0 

func (pg *PrepGeom) ContainsXY(x, y float64) bool

ContainsXY returns if pg contains the point (x, y).

func (*PrepGeom) CoveredBy 

func (pg *PrepGeom) CoveredBy(g *Geom) bool

CoveredBy returns if pg is covered by g.

func (*PrepGeom) Covers 

func (pg *PrepGeom) Covers(g *Geom) bool

Covers returns if pg covers g.

func (*PrepGeom) Crosses 

func (pg *PrepGeom) Crosses(g *Geom) bool

Crosses returns if pg crosses g.

func (*PrepGeom) Disjoint 

func (pg *PrepGeom) Disjoint(g *Geom) bool

Disjoint returns if pg is disjoint from g.

func (*PrepGeom) DistanceWithin added in v0.19.0 

func (pg *PrepGeom) DistanceWithin(g *Geom, dist float64) bool

DistanceWithin returns if pg is within dist g.

func (*PrepGeom) Intersects 

func (pg *PrepGeom) Intersects(g *Geom) bool

Intersects returns if pg contains g.

func (*PrepGeom) IntersectsXY added in v0.19.0 

func (pg *PrepGeom) IntersectsXY(x, y float64) bool

IntersectsXY returns if pg intersects the point at (x, y).

func (*PrepGeom) NearestPoints added in v0.19.0 

func (pg *PrepGeom) NearestPoints(g *Geom) *CoordSeq

NearestPoints returns if pg overlaps g.

func (*PrepGeom) Overlaps 

func (pg *PrepGeom) Overlaps(g *Geom) bool

Overlaps returns if pg overlaps g.

func (*PrepGeom) Touches 

func (pg *PrepGeom) Touches(g *Geom) bool

Touches returns if pg contains g.

func (*PrepGeom) Within 

func (pg *PrepGeom) Within(g *Geom) bool

Within returns if pg is within g.

type RelateBoundaryNodeRule added in v0.12.0 

type RelateBoundaryNodeRule int

A RelateBoundaryNodeRule is a relate boundary node rule. 

const (
	RelateBoundaryNodeRuleMod2                RelateBoundaryNodeRule = C.GEOSRELATE_BNR_MOD2
	RelateBoundaryNodeRuleOGC                 RelateBoundaryNodeRule = C.GEOSRELATE_BNR_OGC
	RelateBoundaryNodeRuleEndpoint            RelateBoundaryNodeRule = C.GEOSRELATE_BNR_ENDPOINT
	RelateBoundaryNodeRuleMultivalentEndpoint RelateBoundaryNodeRule = C.GEOSRELATE_BNR_MULTIVALENT_ENDPOINT
	RelateBoundaryNodeRuleMonovalentEndpoint  RelateBoundaryNodeRule = C.GEOSRELATE_BNR_MONOVALENT_ENDPOINT
)

Boundary node rules.

type STRtree added in v0.12.0 

type STRtree struct {
	// contains filtered or unexported fields
}

An STRtree is an R-tree spatial index structure for two dimensional data.

WARNING The Go bindings to STRtree are currently broken. Do not use them.

func NewSTRtree added in v0.20.2 

func NewSTRtree(nodeCapacity int) *STRtree

NewSTRtree returns a new STRtree with the given number of entries per node.

func (*STRtree) Insert added in v0.12.0 

func (t *STRtree) Insert(g *Geom, value any) error

Insert inserts value with geometry g.

func (*STRtree) Iterate added in v0.12.0 

func (t *STRtree) Iterate(callback func(any))

Iterate calls f for every value in the t.

func (*STRtree) Nearest added in v0.12.0 

func (t *STRtree) Nearest(geom *Geom) *Geom

Nearest returns the nearest geometry to geom in t.

WARNING Nearest is currently broken and always panics with a segmentation fault.

func (*STRtree) NearestGeneric added in v0.20.2 

func (t *STRtree) NearestGeneric(value any, valueEnvelope *Geom, distanceFunc func(any, any) float64) any

NearestGeneric returns the nearest value to value.

WARNING NearestGeneric is currently broken and always panics with a segmentation fault.

func (*STRtree) Query added in v0.12.0 

func (t *STRtree) Query(g *Geom, callback func(any))

Query calls f with each value that intersects g.

func (*STRtree) Remove added in v0.12.0 

func (t *STRtree) Remove(g *Geom, value any) bool

Remove removes value with geometry g from t.

type TypeID added in v0.7.0 

type TypeID int

A TypeID is a geometry type id. 

const (
	TypeIDPoint              TypeID = C.GEOS_POINT
	TypeIDLineString         TypeID = C.GEOS_LINESTRING
	TypeIDLinearRing         TypeID = C.GEOS_LINEARRING
	TypeIDPolygon            TypeID = C.GEOS_POLYGON
	TypeIDMultiPoint         TypeID = C.GEOS_MULTIPOINT
	TypeIDMultiLineString    TypeID = C.GEOS_MULTILINESTRING
	TypeIDMultiPolygon       TypeID = C.GEOS_MULTIPOLYGON
	TypeIDGeometryCollection TypeID = C.GEOS_GEOMETRYCOLLECTION
)

Geometry type ids.

type VoronoiDiagramFlag added in v0.21.0 

type VoronoiDiagramFlag int
const (
	VoronoiDiagramFlagOnlyEdges     VoronoiDiagramFlag = C.GEOS_VORONOI_ONLY_EDGES
	VoronoiDiagramFlagPreserveOrder VoronoiDiagramFlag = C.GEOS_VORONOI_PRESERVE_ORDER
)

Voronoi diagram flags.

type WKBFlavor added in v0.20.2 

type WKBFlavor int

A WKBFlavor is a flavor of WKB. 

const (
	WKBFlavorExtended WKBFlavor = C.GEOS_WKB_EXTENDED
	WKBFlavorISO      WKBFlavor = C.GEOS_WKB_ISO
)

WKB flavors.

type WKBReader added in v0.20.2 

type WKBReader struct {
	// contains filtered or unexported fields
}

A WKBReader reads geometries from WKB (Well Known Binary).

func (*WKBReader) Read added in v0.20.2 

func (r *WKBReader) Read(wkb []byte) (*Geom, error)

Read reads a geometry from wkb.

type WKBWriter added in v0.20.2 

type WKBWriter struct {
	// contains filtered or unexported fields
}

A WKBWriter writes geometries as WKB (Well Known Binary).

func (*WKBWriter) Write added in v0.20.2 

func (w *WKBWriter) Write(g *Geom) []byte

Write returns the WKB representation of g.

type WKBWriterOption added in v0.20.2 

type WKBWriterOption func(*WKBWriter)

A WKBWriterOption sets an option on a WKBWriter.

func WithWKBWriterFlavor added in v0.20.2 

func WithWKBWriterFlavor(flavor WKBFlavor) WKBWriterOption

WithWKBWriterFlavor sets the WKB flavor.

func WithWKBWriterIncludeSRID added in v0.20.2 

func WithWKBWriterIncludeSRID(includeSRID bool) WKBWriterOption

WithWKBWriterIncludeSRID sets whether to include the SRID.

type WKTReader added in v0.20.2 

type WKTReader struct {
	// contains filtered or unexported fields
}

A WKTReader reads geometries from WKT (Well Known Text).

func (*WKTReader) Read added in v0.20.2 

func (r *WKTReader) Read(wkt string) (*Geom, error)

Read reads a geometry from wkt.

type WKTWriter added in v0.20.2 

type WKTWriter struct {
	// contains filtered or unexported fields
}

A WKTWriter writes geometries in WKT (Well Known Text).

func (*WKTWriter) Write added in v0.20.2 

func (w *WKTWriter) Write(g *Geom) string

Write returns the WKT representation of g.

Source Files

View all Source files

Directories

Path Synopsis
examples module
Package geojson implements GEOS-backed GeoJSON.
 Package geojson implements GEOS-backed GeoJSON.
Package geometry provides a GEOS-backed geometry type.
 Package geometry provides a GEOS-backed geometry type.
internal
cmds/execute-template command
execute-template executes a Go template with data.
 execute-template executes a Go template with data.

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