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geo

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togo geo — distances, bounding boxes, nearest & geofencing

togo-framework
bash
togo install togo-framework/geo

Install

bash
togo install togo-framework/geo

Pure-Go geospatial helpers (GeoDjango-lite): great-circle distances, bearings, bounding boxes, polygon/circle geofencing, and nearest/within proximity queries — no external dependencies.

Usage

go
nyc := geo.Point{Lat: 40.7128, Lng: -74.0060}
la  := geo.Point{Lat: 34.0522, Lng: -118.2437}

geo.DistanceKm(nyc, la)        // ≈ 3935 km
geo.Haversine(nyc, la)         // meters
geo.Bearing(nyc, la)           // initial compass bearing (0–360°)

// Geofencing
fence := geo.Circle{Center: nyc, RadiusM: 5000}
fence.Contains(p)              // within 5 km of NYC?
poly := geo.Polygon{{0,0},{0,1},{1,1},{1,0}}
poly.Contains(geo.Point{0.5, 0.5}) // point-in-polygon (ray casting)

// Proximity
geo.Nearest(nyc, points, 5)            // 5 closest points, nearest first
geo.Within(nyc, points, 1000)          // points within 1 km

// Bounding box (cheap pre-filter before exact distance)
box := geo.BoundsAround(nyc, 1000)
box.Contains(p)

Place index

go
ix := geo.NewIndex()
ix.Add(geo.Place{ID: "store-1", Point: nyc, Meta: map[string]any{"name": "HQ"}})
hits := ix.Near(me, 2000)     // []PlaceHit sorted by distance, within 2 km
top  := ix.Nearest(me, 10)    // 10 closest

Point marshals as {"lat":…,"lng":…}; geo.Parse("40.7128,-74.0060") reads "lat,lng".

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