September 2017 Update

Task/Haversine-formula/TechBASIC/haversine-formula.techbasic

@@ -0,0 +1,30 @@
+FUNCTION HAVERSINE
+!---------------------------------------------------------------
+!*** Haversine Formula - Calculate distances by LAT/LONG
+!
+
+!*** LAT/LON of the two locations and Unit of measure are GLOBAL
+!*** as they are defined in the main logic of the program, so they
+!*** available for use in the Function.
+!*** Usage: X=HAVERSINE
+
+
+    Radius=6378.137
+    Lat1=(Lat1*MATH.PI/180)
+    Lon1=(Lon1*MATH.PI/180)
+    Lat2=(Lat2*MATH.PI/180)
+    Lon2=(Lon2*MATH.PI/180)
+    DLon=Lon1-Lon2
+    ANSWER=ACOS(SIN(Lat1)*SIN(Lat2)+COS(Lat1)*COS(Lat2)*COS(DLon))*Radius
+
+    DISTANCE="kilometers"
+    SELECT CASE UNIT
+           CASE "M"
+                HAVERSINE=ANSWER*0.621371192
+                Distance="miles"
+           CASE "N"
+                HAVERSINE=ANSWER*0.539956803
+                Distance="nautical miles"
+    END SELECT
+
+END FUNCTION