Merge pull request #284 from ie3-institute/sp/#283-haversine-speedup

Remove earth radius conversion from calcHaversine

Author: danielfeismann

src/main/java/edu/ie3/util/geo/GeoUtils.java

@@ -154,14 +154,11 @@ public static SortedSet<CoordinateDistance> calcOrderedCoordinateDistances(
    * @param lngA longitude of coordinate a
    * @param latB latitude of coordinate b
    * @param lngB longitude of coordinate b
-   * @return The distance between both coordinates in {@link
-   *     edu.ie3.util.quantities.PowerSystemUnits#KILOMETRE}
+   * @return The distance between both coordinates as a {@link Length}
    */
   public static ComparableQuantity<Length> calcHaversine(
       double latA, double lngA, double latB, double lngB) {
 
-    // average radius of the earth in km
-    ComparableQuantity<Length> r = EARTH_RADIUS.to(KILOMETRE);
     ComparableQuantity<Angle> dLat = Quantities.getQuantity(toRadians(latB - latA), RADIAN);
     ComparableQuantity<Angle> dLon = Quantities.getQuantity(toRadians(lngB - lngA), RADIAN);
     double a =
@@ -171,7 +168,7 @@ public static ComparableQuantity<Length> calcHaversine(
                 * sin(dLon.getValue().doubleValue() / 2)
                 * sin(dLon.getValue().doubleValue() / 2);
     double c = 2 * atan2(sqrt(a), sqrt(1 - a));
-    return r.multiply(c);
+    return EARTH_RADIUS.multiply(c);
   }
 
   /**
@@ -207,7 +204,7 @@ public static ComparableQuantity<Length> totalLengthOfLineString(LineString line
    * @return the length of the linestring as a quantity
    */
   public static ComparableQuantity<Length> calcHaversine(LineString lineString) {
-    ComparableQuantity<Length> y = Quantities.getQuantity(0, KILOMETRE);
+    ComparableQuantity<Length> y = Quantities.getQuantity(0, METRE);
     for (int i = 0; i < lineString.getNumPoints() - 1; i++) {
       y = y.add(calcHaversine(lineString.getCoordinateN(i), lineString.getCoordinateN(i + 1)));
     }

src/test/groovy/edu/ie3/util/geo/GeoUtilsTest.groovy

@@ -171,7 +171,7 @@ class GeoUtilsTest extends Specification {
             ComparableQuantity<Length> y = GeoUtils.calcHaversine(lineString)
 
         then:
-            QuantityUtil.isEquivalentAbs(y, Quantities.getQuantity(3463.37, PowerSystemUnits.KILOMETRE), 10)
+            QuantityUtil.isEquivalentAbs(y, Quantities.getQuantity(3463370, METRE), 10000)
             // Value from Google Maps, error range of +-10 km
     }