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authorAnton Tananaev <anton.tananaev@gmail.com>2020-11-18 22:29:36 -0800
committerAnton Tananaev <anton.tananaev@gmail.com>2020-11-18 22:29:36 -0800
commit6ea7e5229f8a9269cbcee639a0bd6ede3c7ceb88 (patch)
treeaa7c9f5e69126fd590bd1bec4ea7c98618c24a61 /src/main/java/org/traccar/geofence/GeofencePolygon.java
parentda06eb0d1f8732da2b7f1976bb781b24568f6765 (diff)
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Add geofence area calculation
Diffstat (limited to 'src/main/java/org/traccar/geofence/GeofencePolygon.java')
-rw-r--r--src/main/java/org/traccar/geofence/GeofencePolygon.java44
1 files changed, 39 insertions, 5 deletions
diff --git a/src/main/java/org/traccar/geofence/GeofencePolygon.java b/src/main/java/org/traccar/geofence/GeofencePolygon.java
index 2048ba26d..c03a71225 100644
--- a/src/main/java/org/traccar/geofence/GeofencePolygon.java
+++ b/src/main/java/org/traccar/geofence/GeofencePolygon.java
@@ -1,5 +1,5 @@
/*
- * Copyright 2016 Anton Tananaev (anton@traccar.org)
+ * Copyright 2016 - 2020 Anton Tananaev (anton@traccar.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -34,7 +34,7 @@ public class GeofencePolygon extends GeofenceGeometry {
private boolean needNormalize = false;
- private void precalc() {
+ private void preCalculate() {
if (coordinates == null) {
return;
}
@@ -107,14 +107,47 @@ public class GeofencePolygon extends GeofenceGeometry {
return oddNodes;
}
+ private double toRadians(double input) {
+ return input / 180.0 * Math.PI;
+ }
+
+ private double polarTriangleArea(double tan1, double lng1, double tan2, double lng2) {
+ double deltaLng = lng1 - lng2;
+ double t = tan1 * tan2;
+ return 2 * Math.atan2(t * Math.sin(deltaLng), 1 + t * Math.sin(deltaLng));
+ }
+
+ @Override
+ public double calculateArea() {
+ if (coordinates.size() < 3) {
+ return 0;
+ }
+
+ double total = 0;
+ Coordinate prev = coordinates.get(coordinates.size() - 1);
+ double prevTanLat = Math.tan((Math.PI / 2 - toRadians(prev.getLat())) / 2);
+ double prevLng = toRadians(prev.getLon());
+
+ for (Coordinate point : coordinates) {
+ double tanLat = Math.tan((Math.PI / 2 - toRadians(point.getLat())) / 2);
+ double lng = toRadians(point.getLon());
+ total += polarTriangleArea(tanLat, lng, prevTanLat, prevLng);
+ prevTanLat = tanLat;
+ prevLng = lng;
+ }
+
+ double earthRadius = 6371009;
+ return total * (earthRadius * earthRadius);
+ }
+
@Override
public String toWkt() {
StringBuilder buf = new StringBuilder();
buf.append("POLYGON ((");
for (Coordinate coordinate : coordinates) {
- buf.append(String.valueOf(coordinate.getLat()));
+ buf.append(coordinate.getLat());
buf.append(" ");
- buf.append(String.valueOf(coordinate.getLon()));
+ buf.append(coordinate.getLon());
buf.append(", ");
}
return buf.substring(0, buf.length() - 2) + "))";
@@ -158,7 +191,8 @@ public class GeofencePolygon extends GeofenceGeometry {
}
coordinates.add(coordinate);
}
- precalc();
+
+ preCalculate();
}
}