code: func (b *Bound) GeoWidth(haversine ...bool) float64 {
  	c := b.Center()
  
  	A := &Point{b.sw[0], c[1]}
  	B := &Point{b.ne[0], c[1]}
  
  	return A.GeoDistanceFrom(B, yesHaversine(haversine))
  }
docs: // GeoWidth returns the approximate width in meters
  // of the center of the bound.  Only applies if
  // the data is Lng/Lat degrees.