tgo

Go bindings for tidwall/tg Geometry library for C - Fast point-in-polygon

This is partial but functional, tg is a very small self contained C library, tgo compiles tg, no external dependencies needed.

Usage

Simply go get this library with CGO enabled (you'll need a C compiler).

Read from WKT

// Unmarshal from WKT
input := "POLYGON((0 0,0 1,1 1,1 0,0 0))"
g, _ := tgo.UnmarshalWKT(input)

// Marshal to WKT
output := g.AsText()
fmt.Println(output) // Prints: POLYGON((0 0,0 1,1 1,1 0,0 0))

Read from GeoJSON

input := `{"type":"Feature","properties":{},"geometry":{"coordinates":[-79.20159897229003,43.636785010689835],"type":"Point"}}`
g, _ := tgo.UnmarshalGeoJSON(input)

Read from WKB

input := []byte{1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 248, 63, 0, 0, 0, 0, 0, 0, 4, 64}
g, _ := tgo.UnmarshalWKB(input)

Intersects

if Intersects(g1, g2) {
	fmt.Println("Intersects")
}

Point in Polygon on large FeatureCollections

// load your collection using UnmarshalGeoJSON
found := g.StabOne(2, 48)
if found != nil {
	fmt.Println(found.Properties())
}
// Output: {"properties":{ "ADMIN": "France", "ISO_A2": "FR", "ISO_A3": "FRA" }}

Types

input := "POLYGON((0 0,0 1,1 1,1 0,0 0))"
g, _ := tgo.UnmarshalWKT(input)

if g.Types() == tgo.Polygon() {
	p, _ := g.AsPoly()
	p.HolesCount()
}

Tests

Some tests are borrowed from simplefeatures.