Add GeoDistance

langext/compare.go

@@ -30,3 +30,34 @@ func CompareIntArr(arr1 []int, arr2 []int) bool {
 
 	return false
 }
+
+func CompareArr[T OrderedConstraint](arr1 []T, arr2 []T) bool {
+
+	for i := 0; i < len(arr1) || i < len(arr2); i++ {
+
+		if i < len(arr1) && i < len(arr2) {
+
+			if arr1[i] < arr2[i] {
+				return true
+			} else if arr1[i] > arr2[i] {
+				return false
+			} else {
+				continue
+			}
+
+		}
+
+		if i < len(arr1) {
+
+			return true
+
+		} else { // if i < len(arr2)
+
+			return false
+
+		}
+
+	}
+
+	return false
+}

langext/coords.go

@@ -0,0 +1,21 @@
+package langext
+
+import "math"
+
+func DegToRad(deg float64) float64 {
+	return deg * (math.Pi / 180.0)
+}
+
+func RadToDeg(rad float64) float64 {
+	return rad / (math.Pi * 180.0)
+}
+
+func GeoDistance(lon1 float64, lat1 float64, lon2 float64, lat2 float64) float64 {
+	var d1 = DegToRad(lat1)
+	var num1 = DegToRad(lon1)
+	var d2 = DegToRad(lat2)
+	var num2 = DegToRad(lon2) - num1
+	var d3 = math.Pow(math.Sin((d2-d1)/2.0), 2.0) + math.Cos(d1)*math.Cos(d2)*math.Pow(math.Sin(num2/2.0), 2.0)
+
+	return 6376500.0 * (2.0 * math.Atan2(math.Sqrt(d3), math.Sqrt(1.0-d3)))
+}