Moved rectangle padding to 1:100 to only maxDepth

instead of the actual search space.

community/spatial-index/src/main/java/org/neo4j/gis/spatial/index/Envelope.java

@@ -23,6 +23,8 @@
 
 public class Envelope
 {
+    private static final double MAXIMAL_ENVELOPE_SIDE_RATIO = 100;
+
     protected final double[] min;
     protected final double[] max;
 
@@ -55,6 +57,31 @@ public Envelope( double xmin, double xmax, double ymin, double ymax )
         this( new double[] { xmin, ymin }, new double[] { xmax, ymax } );
     }
 
+    /**
+     * @return a copy of the envelope where the ratio of smallest to largest side is not more than 1:100
+     */
+    public Envelope withSideRatioNotTooSmall( )
+    {
+        double[] from = Arrays.copyOf( this.min, min.length );
+        double[] to = Arrays.copyOf( this.max, max.length );
+        double highestDiff = -Double.MAX_VALUE;
+        double[] diffs = new double[from.length];
+        for ( int i = 0; i < from.length; i++ )
+        {
+            diffs[i] = to[i] - from[i];
+            highestDiff = Math.max( highestDiff, diffs[i] );
+        }
+        final double mindiff = highestDiff / MAXIMAL_ENVELOPE_SIDE_RATIO;
+        for ( int i = 0; i < from.length; i++ )
+        {
+            if ( diffs[i] < mindiff )
+            {
+                to[i] = from[i] + mindiff;
+            }
+        }
+        return new Envelope( from, to );
+    }
+
     public double[] getMin()
     {
         return min;

community/spatial-index/src/main/java/org/neo4j/gis/spatial/index/curves/SpaceFillingCurve.java

@@ -30,8 +30,6 @@
 
 public abstract class SpaceFillingCurve
 {
-
-    private static final double MAXIMAL_ENVELOPE_SIDE_RATIO = 100;
     /**
      * Description of the space filling curve structure
      */
@@ -284,30 +282,10 @@ else if ( toOrNull == null )
                 }
             }
         }
-        ensureSideRatioNotTooSmall( from, to );
         Envelope referenceEnvelope = new Envelope( from, to );
         return getTilesIntersectingEnvelope( referenceEnvelope, config, null );
     }
 
-    static void ensureSideRatioNotTooSmall( double[] from, double[] to )
-    {
-        double highestDiff = -Double.MAX_VALUE;
-        double[] diffs = new double[from.length];
-        for ( int i = 0; i < from.length; i++ )
-        {
-            diffs[i] = to[i] - from[i];
-            highestDiff = Math.max( highestDiff, diffs[i] );
-        }
-        final double mindiff = highestDiff / MAXIMAL_ENVELOPE_SIDE_RATIO;
-        for ( int i = 0; i < from.length; i++ )
-        {
-            if ( diffs[i] < mindiff )
-            {
-                to[i] = from[i] + mindiff;
-            }
-        }
-    }
-
     List<LongRange> getTilesIntersectingEnvelope( Envelope referenceEnvelope, SpaceFillingCurveConfiguration config, SpaceFillingCurveMonitor monitor )
     {
         SearchEnvelope search = new SearchEnvelope( this, referenceEnvelope );

community/spatial-index/src/main/java/org/neo4j/gis/spatial/index/curves/StandardConfiguration.java

@@ -64,7 +64,8 @@ public boolean stopAtThisDepth( double overlap, int depth, int maxDepth )
     @Override
     public int maxDepth( Envelope referenceEnvelope, Envelope range, int nbrDim, int maxLevel )
     {
-        double searchRatio = range.getArea() / referenceEnvelope.getArea();
+        Envelope paddedEnvelope = referenceEnvelope.withSideRatioNotTooSmall();
+        double searchRatio = range.getArea() / paddedEnvelope.getArea();
         if ( Double.isInfinite( searchRatio ) )
         {
             return maxLevel;

community/spatial-index/src/test/java/org/neo4j/gis/spatial/index/EnvelopeTest.java

@@ -24,6 +24,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.closeTo;
 import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertTrue;
 
 public class EnvelopeTest
@@ -106,6 +107,49 @@ public void shouldHandleIntersectionsIn2D()
         testOverlaps(left, new Envelope( 0.5, 1.5, 0.0, 1.0 ), true, 0.5, 0.5);        // overlaps right half
     }
 
+    @Test
+    public void testWithSideRatioNotTooSmall2D()
+    {
+        // No change expected
+        double[] from = new double[] {0, 0};
+        double[] to = new double[] {1, 1};
+
+        Envelope envelope = new Envelope( from, to ).withSideRatioNotTooSmall();
+        double[] expectedFrom = new double[] {0, 0};
+        double[] expectedTo = new double[] {1, 1};
+        assertArrayEquals( expectedFrom, envelope.min , 0);
+        assertArrayEquals( expectedTo, envelope.max, 0 );
+
+        // Expected to change
+        to = new double[] {100, 0.1};
+        Envelope envelope2 = new Envelope( from, to ).withSideRatioNotTooSmall();
+        double[] expectedTo2 = new double[] {100, 1};
+        assertArrayEquals( expectedFrom, envelope2.min , 0);
+        assertArrayEquals( expectedTo2, envelope2.max, 0.00001 );
+    }
+
+    // Works for any number of dimensions, and 4 is more interesting than 3
+    @Test
+    public void testWithSideRatioNotTooSmall4D()
+    {
+        // No change expected
+        double[] from = new double[] {0, 0, 0, 0};
+        double[] to = new double[] {1, 1, 1, 1};
+
+        Envelope envelope = new Envelope( from, to ).withSideRatioNotTooSmall();
+        double[] expectedFrom = new double[] {0, 0, 0, 0};
+        double[] expectedTo = new double[] {1, 1, 1, 1};
+        assertArrayEquals( expectedFrom, envelope.min , 0);
+        assertArrayEquals( expectedTo, envelope.max, 0 );
+
+        // Expected to change
+        to = new double[] {100, 0.1, 12, 0.01};
+        Envelope envelope2 = new Envelope( from, to ).withSideRatioNotTooSmall();
+        double[] expectedTo2 = new double[] {100, 1, 12, 1};
+        assertArrayEquals( expectedFrom, envelope2.min , 0);
+        assertArrayEquals( expectedTo2, envelope2.max, 0.00001 );
+    }
+
     private void makeAndTestEnvelope( double[] min, double[] max, double[] width )
     {
         Envelope env = new Envelope( min, max );

community/spatial-index/src/test/java/org/neo4j/gis/spatial/index/curves/SpaceFillingCurveTest.java

@@ -1006,49 +1006,6 @@ public void shouldNotStepMoreThanDistanceOneMoreThan10Percent()
         }
     }
 
-    @Test
-    public void testEnsureSideRatioNotTooSmall2D()
-    {
-        // No change expected
-        double[] from = new double[] {0, 0};
-        double[] to = new double[] {1, 1};
-
-        SpaceFillingCurve.ensureSideRatioNotTooSmall( from, to );
-        double[] expectedFrom = new double[] {0, 0};
-        double[] expectedTo = new double[] {1, 1};
-        assertArrayEquals( expectedFrom, from , 0);
-        assertArrayEquals( expectedTo, to, 0 );
-
-        // Expected to change
-        to = new double[] {100, 0.1};
-        SpaceFillingCurve.ensureSideRatioNotTooSmall( from, to );
-        double[] expectedTo2 = new double[] {100, 1};
-        assertArrayEquals( expectedFrom, from , 0);
-        assertArrayEquals( expectedTo2, to, 0.00001 );
-    }
-
-    // Works for any number of dimensions, and 4 is more interesting than 3
-    @Test
-    public void testEnsureSideRatioNotTooSmall4D()
-    {
-        // No change expected
-        double[] from = new double[] {0, 0, 0, 0};
-        double[] to = new double[] {1, 1, 1, 1};
-
-        SpaceFillingCurve.ensureSideRatioNotTooSmall( from, to );
-        double[] expectedFrom = new double[] {0, 0, 0, 0};
-        double[] expectedTo = new double[] {1, 1, 1, 1};
-        assertArrayEquals( expectedFrom, from , 0);
-        assertArrayEquals( expectedTo, to, 0 );
-
-        // Expected to change
-        to = new double[] {100, 0.1, 12, 0.01};
-        SpaceFillingCurve.ensureSideRatioNotTooSmall( from, to );
-        double[] expectedTo2 = new double[] {100, 1, 12, 1};
-        assertArrayEquals( expectedFrom, from , 0);
-        assertArrayEquals( expectedTo2, to, 0.00001 );
-    }
-
     private void shouldNeverStepMoreThanDistanceOne( SpaceFillingCurve curve, int level, int badnessThresholdPercentage )
     {
         int badCount = 0;