Polylines without duplicate consecutive shape points (#55)

osmlab · Jan 12, 2018 · 1c9c2c4 · 1c9c2c4
1 parent 3fa7f26
commit 1c9c2c4
Show file tree

Hide file tree

Showing 2 changed files with 52 additions and 0 deletions.
diff --git a/src/main/java/org/openstreetmap/atlas/geography/PolyLine.java b/src/main/java/org/openstreetmap/atlas/geography/PolyLine.java
@@ -1074,6 +1074,37 @@ public String toWkt()
         return new WktPolyLineConverter().convert(this);
     }
 
+    /**
+     * @return This {@link PolyLine} without duplicate consecutive shape points. Non-consecutive
+     *         shape points will remain unchanged.
+     */
+    public PolyLine withoutDuplicateConsecutiveShapePoints()
+    {
+        final List<Location> shapePoints = new ArrayList<>();
+        boolean hasDuplicates = false;
+
+        final Iterator<Location> locationIterator = this.iterator();
+        // PolyLines are only valid if at least one point exists, so it is safe to call next() once.
+        Location previousLocation = locationIterator.next();
+        shapePoints.add(previousLocation);
+
+        while (locationIterator.hasNext())
+        {
+            final Location currentLocation = locationIterator.next();
+
+            if (!currentLocation.equals(previousLocation))
+            {
+                shapePoints.add(currentLocation);
+            }
+            else
+            {
+                hasDuplicates = true;
+            }
+            previousLocation = currentLocation;
+        }
+        return hasDuplicates ? new PolyLine(shapePoints) : this;
+    }
+
     protected final List<Location> getPoints()
     {
         return this.points;

diff --git a/src/test/java/org/openstreetmap/atlas/geography/PolyLineTest.java b/src/test/java/org/openstreetmap/atlas/geography/PolyLineTest.java
@@ -167,4 +167,25 @@ public void testToString()
                 multipleLocationPolyLine.toString());
     }
 
+    @Test
+    public void testWithoutDuplicateConsecutiveShapePoints()
+    {
+        final PolyLine polyLine1 = PolyLine.wkt(
+                "LINESTRING (-75.616326 40.194564, -75.616330 40.194570, -75.616330 40.194570, -75.616340 40.194580)");
+        final PolyLine polyLine2 = PolyLine.wkt(
+                "LINESTRING (-75.616326 40.194564, -75.616330 40.194570, -75.616340 40.194580)");
+        final PolyLine polyLine3 = PolyLine.wkt(
+                "LINESTRING (-75.616326 40.194564, -75.616330 40.194570, -75.616340 40.194580, -75.616330 40.194570)");
+        final PolyLine polyLine4 = PolyLine.wkt(
+                "LINESTRING (-75.616330 40.194570, -75.616330 40.194570, -75.616330 40.194570, -75.616340 40.194580, -75.616340 40.194590)");
+        final PolyLine polyLine5 = PolyLine.wkt(
+                "LINESTRING (-75.616330 40.194570, -75.616340 40.194580, -75.616340 40.194590)");
+        Assert.assertEquals(polyLine2.toWkt(),
+                polyLine1.withoutDuplicateConsecutiveShapePoints().toWkt());
+        Assert.assertEquals(polyLine3.toWkt(),
+                polyLine3.withoutDuplicateConsecutiveShapePoints().toWkt());
+        Assert.assertEquals(polyLine5.toWkt(),
+                polyLine4.withoutDuplicateConsecutiveShapePoints().toWkt());
+    }
+
 }