govitia / geocalc

Go minimalist library to compute earth points. Implementation of https://www.movable-type.co.uk/scripts/latlong.html.

Geocalc

Go minimalist library to compute earth points. Implementation of https://www.movable-type.co.uk/scripts/latlong.html. Angle are in Rad and distance in meters.

Features in v1.3.3

• Earth points in Rad/Degree
• Get distance between two Points
• Create Walk line
• Get bearing between two Points
• Rad/Degree conversion functions

Quick start

Creating Points

// Point creation is in Rad
p1 := geocalc.NewPoint(math.Pi, 0)
p2 := geocalc.NewPoint(0, 0)

// Get degree values for p1
latDegree, lonDegree := p1.Degree()

Bearing and distance

// Get bearing in Rad between two Points
bearing := p1.Bearing(p2)
bearing := p2.Bearing(p1)
// Distance in meters
distance := geocalc.Distance(p1, p2)

Unit conversion

rad := math.Pi
degree := geocalc.RadToDegree(rad) // 180
rad = geocalc.DegreeToRad(degree)  // math.Pi

Walking on the earth surface

Walk from a starting point to a final point with a bearing of 0 Rad and a distance of 1000m

startPoint := geocalc.NewPoint(0, 0)
finalPoint := startPoint.Walk(0, 1000) // Return a new point 

Intermediate Points

Intermediate calculate an intermediate point at any fraction along the great circle path between p1 and p2. Start path at p1, if fraction=0, returned Point is p1. If fraction=1, returned Point is p2.

p1 := geocalc.NewPoint(math.Pi, 0)
p2 := geocalc.NewPoint(0, 0)
fraction := 0.5 // We want a Point in the middle of the other two Points
p3 := geocalc.Intermediate(p1, p2, fraction)