Implemented and tested to check if a point is inside or outside of a boundary using a ray tracing algorithm. The function is public static for a GPSCoordinate and takes a list of GPSCoordinates and the comparing coordinate. #story[873]

mock/src/main/java/seng302/Model/GPSCoordinate.java

@@ -1,5 +1,8 @@
 package seng302.Model;
 
+import java.util.Comparator;
+import java.util.List;
+
 /**
  * GPS Coordinate for the world map.
  * Created by esa46 on 15/03/17.
@@ -68,5 +71,90 @@ public class GPSCoordinate {
         result = 31 * result + (int) (temp ^ (temp >>> 32));
         return result;
     }
+
+    /**
+     * Calculates min and max values and passed it to calculate if coordinate is in the boundary
+     * @param coordinate coordinate of interest
+     * @param boundary List of points which make a boundry
+     * @return true if coordinate is in the boundary
+     */
+    public static boolean isInsideBoundary(GPSCoordinate coordinate, List<GPSCoordinate> boundary) {
+        double maxLatitude = boundary.stream().max(Comparator.comparingDouble(GPSCoordinate::getLatitude)).get().getLatitude();
+        double maxLongitude = boundary.stream().max(Comparator.comparingDouble(GPSCoordinate::getLongitude)).get().getLongitude();
+        double minLatitude = boundary.stream().min(Comparator.comparingDouble(GPSCoordinate::getLatitude)).get().getLatitude();
+        double minLongitude = boundary.stream().min(Comparator.comparingDouble(GPSCoordinate::getLongitude)).get().getLongitude();
+        return isInsideBoundary(coordinate, boundary, new GPSCoordinate(minLatitude, minLongitude),
+                new GPSCoordinate(maxLatitude, maxLongitude));
+    }
+
+    /**
+     * Calculates if the coordinate is in the boundary
+     * @param coordinate coordinate of interest
+     * @param boundary List of points which make a boundary
+     * @param minValues max GPS
+     * @param maxValues min GPS
+     * @return true if coordinate is in the boundary
+     */
+    public static boolean isInsideBoundary(GPSCoordinate coordinate, List<GPSCoordinate> boundary, GPSCoordinate minValues, GPSCoordinate maxValues) {
+        double minLat = minValues.getLatitude();
+        double minLon = minValues.getLongitude();
+        double maxLat = maxValues.getLatitude();
+        double maxLon = maxValues.getLongitude();
+        double coordinateLat = coordinate.getLatitude();
+        double coordinateLon = coordinate.getLongitude();
+        int length = boundary.size();
+
+        boolean inside = false;
+
+        // End computation early
+        if (coordinateLat <= minLat || coordinateLat >= maxLat || coordinateLon <= minLon || coordinateLon >= maxLon) {
+            return false;
+        }
+
+        // Check if inside using ray casting algorithm
+        for (int i = 0, j = length - 1; i < length; j = i++) {
+            if (intersects(boundary.get(i), boundary.get(j), coordinate)) {
+                inside = !inside;
+            }
+
+
+        }
+        return inside;
+    }
+
+    /**
+     * Helper function to find if a point is in a boundary
+     * @param boundaryA
+     * @param boundaryB
+     * @param coordinate
+     * @return true if a line from the point intersects the two boundary points
+     */
+    private static boolean intersects(GPSCoordinate boundaryA, GPSCoordinate boundaryB, GPSCoordinate coordinate) {
+        double boundaryALat = boundaryA.getLatitude();
+        double boundaryALon = boundaryA.getLongitude();
+        double boundaryBLat = boundaryB.getLatitude();
+        double boundaryBLon = boundaryB.getLongitude();
+        double coordinateLat = coordinate.getLatitude();
+        double coordinateLon = coordinate.getLongitude();
+
+        if (boundaryALat > boundaryBLat) {
+            return intersects(boundaryB, boundaryA, coordinate);
+        }
+        if (coordinateLat == boundaryALat || coordinateLat == boundaryBLat) {
+            // Move coordinate off intersection line
+            coordinateLat += 1e-9;
+        }
+        if (coordinateLat > boundaryBLat || coordinateLat < boundaryALat || coordinateLon > Double.max(boundaryALon, boundaryBLon)) {
+            return false;
+        }
+        if (coordinateLon < Double.min(boundaryALon, boundaryBLon)) {
+            return true;
+        }
+
+        double aRatio = (coordinateLat - boundaryALat) / (coordinateLon - boundaryALon);
+        double bRatio = (coordinateLat - boundaryBLat) / (coordinateLon - boundaryBLon);
+        return aRatio >= bRatio;
+
+    }
 }
 

mock/src/test/java/seng302/Model/GPSCoordinateTest.java

@@ -0,0 +1,121 @@
+package seng302.Model;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import static junit.framework.TestCase.assertTrue;
+import static junit.framework.TestCase.assertFalse;
+
+/**
+ * Created by jjg64 on 11/05/17.
+ */
+public class GPSCoordinateTest {
+    List<GPSCoordinate> boundary;
+
+    @Before
+    public void init() {
+        boundary = new ArrayList<>();
+    }
+
+    /**
+     * -------
+     * |     |
+     * |   * |
+     * -------
+     */
+    @Test
+    public void insideSquareTest() {
+        boundary.add(new GPSCoordinate(0, 0));
+        boundary.add(new GPSCoordinate(10, 0));
+        boundary.add(new GPSCoordinate(10, 10));
+        boundary.add(new GPSCoordinate(0, 10));
+
+        GPSCoordinate coordinate = new GPSCoordinate(2, 8);
+        boolean inside = GPSCoordinate.isInsideBoundary(coordinate, boundary);
+        assertTrue(inside);
+    }
+
+    /**
+     *   -------
+     *   |     |
+     * * |     |
+     *   -------
+     */
+    @Test
+    public void outsideSquareTest() {
+        boundary.add(new GPSCoordinate(0, 0));
+        boundary.add(new GPSCoordinate(10, 0));
+        boundary.add(new GPSCoordinate(10, 10));
+        boundary.add(new GPSCoordinate(0, 10));
+
+        GPSCoordinate coordinate = new GPSCoordinate(-2, 8);
+        boolean inside = GPSCoordinate.isInsideBoundary(coordinate, boundary);
+        assertFalse(inside);
+    }
+
+    /**
+     * -------
+     * |     |
+     * |     |
+     * *------
+     */
+    @Test
+    public void edgeSquareTest() {
+        boundary.add(new GPSCoordinate(0, 0));
+        boundary.add(new GPSCoordinate(10, 0));
+        boundary.add(new GPSCoordinate(10, 10));
+        boundary.add(new GPSCoordinate(0, 10));
+
+        GPSCoordinate coordinate = new GPSCoordinate(0, 0);
+        boolean inside = GPSCoordinate.isInsideBoundary(coordinate, boundary);
+        assertFalse(inside);
+    }
+
+    @Test
+    public void insideShapeWithObtuseAnglesTest() {
+        boundary.add(new GPSCoordinate(0, 0));
+        boundary.add(new GPSCoordinate(4, 4));
+        boundary.add(new GPSCoordinate(7, 2));
+        boundary.add(new GPSCoordinate(9, 5));
+        boundary.add(new GPSCoordinate(10, 10));
+        boundary.add(new GPSCoordinate(6, 6));
+        boundary.add(new GPSCoordinate(2, 10));
+
+        GPSCoordinate coordinate = new GPSCoordinate(5, 5);
+        boolean inside = GPSCoordinate.isInsideBoundary(coordinate, boundary);
+        assertTrue(inside);
+    }
+
+    @Test
+    public void outsideShapeWithObtuseAnglesTest() {
+        boundary.add(new GPSCoordinate(0, 0));
+        boundary.add(new GPSCoordinate(4, 4));
+        boundary.add(new GPSCoordinate(7, 2));
+        boundary.add(new GPSCoordinate(9, 5));
+        boundary.add(new GPSCoordinate(10, 10));
+        boundary.add(new GPSCoordinate(6, 6));
+        boundary.add(new GPSCoordinate(2, 10));
+
+        GPSCoordinate coordinate = new GPSCoordinate(4, 3);
+        boolean inside = GPSCoordinate.isInsideBoundary(coordinate, boundary);
+        assertFalse(inside);
+    }
+
+    @Test
+    public void edgeOfShapeWithObtuseAnglesTest() {
+        boundary.add(new GPSCoordinate(0, 0));
+        boundary.add(new GPSCoordinate(4, 4));
+        boundary.add(new GPSCoordinate(7, 2));
+        boundary.add(new GPSCoordinate(9, 5));
+        boundary.add(new GPSCoordinate(10, 10));
+        boundary.add(new GPSCoordinate(6, 6));
+        boundary.add(new GPSCoordinate(2, 10));
+
+        GPSCoordinate coordinate = new GPSCoordinate(2, 10);
+        boolean inside = GPSCoordinate.isInsideBoundary(coordinate, boundary);
+        assertFalse(inside);
+    }
+}