From 66b62de750e75e1081ac8eeccca17f11b297d01a Mon Sep 17 00:00:00 2001
From: Anton Tananaev <anton.tananaev@gmail.com>
Date: Wed, 3 Sep 2014 00:09:42 +1200
Subject: Implement position filtering (fix #259)

---
 src/org/traccar/helper/DistanceCalculator.java | 33 ++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 src/org/traccar/helper/DistanceCalculator.java

(limited to 'src/org/traccar/helper')

diff --git a/src/org/traccar/helper/DistanceCalculator.java b/src/org/traccar/helper/DistanceCalculator.java
new file mode 100644
index 000000000..072f3d7a8
--- /dev/null
+++ b/src/org/traccar/helper/DistanceCalculator.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2014 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * 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.
+ */
+package org.traccar.helper;
+
+public class DistanceCalculator {
+
+    private static final double equatorialEarthRadius = 6378.1370D;
+    private static final double deg2rad = (Math.PI / 180);
+
+    public static double distance(double lat1, double lon1, double lat2, double lon2) {
+        double dlong = (lon2 - lon1) * deg2rad;
+        double dlat = (lat2 - lat1) * deg2rad;
+        double a = Math.pow(Math.sin(dlat / 2), 2) +
+                Math.cos(lat1 * deg2rad) * Math.cos(lat2 * deg2rad) * Math.pow(Math.sin(dlong / 2), 2);
+        double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+        double d = equatorialEarthRadius * c;
+        return d * 1000;
+    }
+
+}
-- 
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