sort features before merging

onthegomap · Sep 25, 2023 · c0fa519 · c0fa519
1 parent 1b53493
commit c0fa519
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diff --git a/planetiler-core/src/main/java/com/onthegomap/planetiler/FeatureMerge.java b/planetiler-core/src/main/java/com/onthegomap/planetiler/FeatureMerge.java
@@ -14,6 +14,7 @@
 import java.util.ArrayList;
 import java.util.BitSet;
 import java.util.Collection;
+import java.util.Comparator;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -117,6 +118,7 @@ private static List<VectorTile.Feature> mergeGeometries(
     List<VectorTile.Feature> features,
     GeometryType geometryType
   ) {
+    features = features.stream().sorted(Comparator.comparingInt(f -> f.geometry().index())).toList();
     List<VectorTile.Feature> result = new ArrayList<>(features.size());
     var groupedByAttrs = groupByAttrs(features, result, geometryType);
     for (List<VectorTile.Feature> groupedFeatures : groupedByAttrs) {

diff --git a/planetiler-core/src/main/java/com/onthegomap/planetiler/VectorTile.java b/planetiler-core/src/main/java/com/onthegomap/planetiler/VectorTile.java
@@ -26,6 +26,7 @@
 import com.onthegomap.planetiler.geo.GeometryException;
 import com.onthegomap.planetiler.geo.GeometryType;
 import com.onthegomap.planetiler.geo.MutableCoordinateSequence;
+import com.onthegomap.planetiler.util.Hilbert;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -923,6 +924,13 @@ public VectorGeometry filterPointsOutsideBuffer(double buffer) {
         return this;
       }
     }
+
+    public int index() {
+      // 0 -> 4096*2*2
+      int x = commands[1];
+      int y = commands[2];
+      return Hilbert.hilbertXYToIndex(14, x, y);
+    }
   }
 
   /**