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+/*******************************************************************************
+ * ============LICENSE_START====================================================
+ * * org.onap.aai
+ * * ===========================================================================
+ * * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ * * Copyright © 2017 Amdocs
+ * * ===========================================================================
+ * * Licensed under the Apache License, Version 2.0 (the "License");
+ * * you may not use this file except in compliance with the License.
+ * * You may obtain a copy of the License at
+ * *
+ * * http://www.apache.org/licenses/LICENSE-2.0
+ * *
+ * * Unless required by applicable law or agreed to in writing, software
+ * * distributed under the License is distributed on an "AS IS" BASIS,
+ * * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * * See the License for the specific language governing permissions and
+ * * limitations under the License.
+ * * ============LICENSE_END====================================================
+ * *
+ * * ECOMP is a trademark and service mark of AT&T Intellectual Property.
+ * *
+ ******************************************************************************/
+package com.att.cadi.routing;
+
+import com.att.inno.env.util.Split;
+
+public class GreatCircle {
+ // Note: multiplying by this constant is faster than calling Math equivalent function
+ private static final double DEGREES_2_RADIANS = Math.PI/180.0;
+
+ public static final double DEGREES_2_NM = 60;
+ public static final double DEGREES_2_KM = DEGREES_2_NM * 1.852; // 1.852 is exact ratio per 1929 Standard Treaty, adopted US 1954
+ public static final double DEGREES_2_MI = DEGREES_2_NM * 1.1507795;
+
+ /**
+ *
+ * Calculate the length of an arc on a perfect sphere based on Latitude and Longitudes of two points
+ * Parameters are in Degrees (i.e. the coordinate system you get from GPS, Mapping WebSites, Phones, etc)
+ *
+ * L1 = Latitude of point A
+ * G1 = Longitude of point A
+ * L2 = Latitude of point B
+ * G2 = Longitude of point B
+ *
+ * d = acos (sin(L1)*sin(L2) + cos(L1)*cos(L2)*cos(G1 - G2))
+ *
+ * Returns answer in Degrees
+ *
+ * Since there are 60 degrees per nautical miles, you can convert to NM by multiplying by 60
+ *
+ * Essential formula from a Princeton website, the "Law of Cosines" method.
+ *
+ * Refactored cleaned up for speed 3/8/2013
+ *
+ * @param latA
+ * @param lonA
+ * @param latB
+ * @param lonB
+ * @return
+ */
+ public static double calc(double latA, double lonA, double latB, double lonB) {
+ // Formula requires Radians. Expect Params to be Coordinates (Degrees)
+ // Simple ratio, quicker than calling Math.toRadians()
+ latA *= DEGREES_2_RADIANS;
+ lonA *= DEGREES_2_RADIANS;
+ latB *= DEGREES_2_RADIANS;
+ lonB *= DEGREES_2_RADIANS;
+
+ return Math.acos(
+ Math.sin(latA) * Math.sin(latB) +
+ Math.cos(latA) * Math.cos(latB) * Math.cos(lonA-lonB)
+ )
+ / DEGREES_2_RADIANS;
+ }
+
+ /**
+ * Convert from "Lat,Long Lat,Long" String format
+ * "Lat,Long,Lat,Long" Format
+ * or all four entries "Lat Long Lat Long"
+ *
+ * (Convenience function)
+ *
+ * Since Distance is positive, a "-1" indicates an error in String formatting
+ */
+ public static double calc(String ... coords) {
+ try {
+ String [] array;
+ switch(coords.length) {
+ case 1:
+ array = Split.split(',',coords[0]);
+ if(array.length!=4)return -1;
+ return calc(
+ Double.parseDouble(array[0]),
+ Double.parseDouble(array[1]),
+ Double.parseDouble(array[2]),
+ Double.parseDouble(array[3])
+ );
+ case 2:
+ array = Split.split(',',coords[0]);
+ String [] array2 = Split.split(',',coords[1]);
+ if(array.length!=2 || array2.length!=2)return -1;
+ return calc(
+ Double.parseDouble(array[0]),
+ Double.parseDouble(array[1]),
+ Double.parseDouble(array2[0]),
+ Double.parseDouble(array2[1])
+ );
+ case 4:
+ return calc(
+ Double.parseDouble(coords[0]),
+ Double.parseDouble(coords[1]),
+ Double.parseDouble(coords[2]),
+ Double.parseDouble(coords[3])
+ );
+
+ default:
+ return -1;
+ }
+ } catch (NumberFormatException e) {
+ return -1;
+ }
+ }
+
+}
+
+///**
+//* Haverside method, from Princeton
+//*
+//* @param alat
+//* @param alon
+//* @param blat
+//* @param blon
+//* @return
+//*/
+//public static double calc3(double alat, double alon, double blat, double blon) {
+// alat *= DEGREES_2_RADIANS;
+// alon *= DEGREES_2_RADIANS;
+// blat *= DEGREES_2_RADIANS;
+// blon *= DEGREES_2_RADIANS;
+// return 2 * Math.asin(
+// Math.min(1, Math.sqrt(
+// Math.pow(Math.sin((blat-alat)/2), 2) +
+// (Math.cos(alat)*Math.cos(blat)*
+// Math.pow(
+// Math.sin((blon-alon)/2),2)
+// )
+// )
+// )
+// )
+// / DEGREES_2_RADIANS;
+//}
+//
+
+
+
+//This is a MEAN radius. The Earth is not perfectly spherical
+// public static final double EARTH_RADIUS_KM = 6371.0;
+// public static final double EARTH_RADIUS_NM = 3440.07;
+// public static final double KM_2_MILES_RATIO = 0.621371192;
+///**
+//* Code on Internet based on Unknown book. Lat/Long is in Degrees
+//* @param alat
+//* @param alon
+//* @param blat
+//* @param blon
+//* @return
+//*/
+//public static double calc1(double alat, double alon, double blat, double blon) {
+// alat *= DEGREES_2_RADIANS;
+// alon *= DEGREES_2_RADIANS;
+// blat *= DEGREES_2_RADIANS;
+// blon *= DEGREES_2_RADIANS;
+//
+// // Reused values
+// double cosAlat,cosBlat;
+//
+// return Math.acos(
+// ((cosAlat=Math.cos(alat))*Math.cos(alon)*(cosBlat=Math.cos(blat))*Math.cos(blon)) +
+// (cosAlat*Math.sin(alon)*cosBlat*Math.sin(blon)) +
+// (Math.sin(alat)*Math.sin(blat))
+// )/DEGREES_2_RADIANS;
+//
+//}
+
+/*
+* This method was 50% faster than calculation 1, and 75% than the Haverside method
+* Also, since it's based off of Agree standard Degrees of the Earth, etc, the calculations are more exact,
+* at least for Nautical Miles and Kilometers
+*/