From c93152a3f05553aba856045ca1d1863a12dc7340 Mon Sep 17 00:00:00 2001
From: Kristin Cowalcijk <bo@wherobots.com>
Date: Thu, 22 Jan 2026 08:57:54 +0800
Subject: [PATCH 1/2] Fix polygon split by line by replicating the logic from
 PostGIS

---
 .../sedona/common/utils/GeometrySplitter.java | 19 ++++++---
 .../apache/sedona/common/FunctionsTest.java   | 41 +++++++++++++++++++
 2 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/common/src/main/java/org/apache/sedona/common/utils/GeometrySplitter.java b/common/src/main/java/org/apache/sedona/common/utils/GeometrySplitter.java
index 7045316fed3..89473c5d3c7 100644
--- a/common/src/main/java/org/apache/sedona/common/utils/GeometrySplitter.java
+++ b/common/src/main/java/org/apache/sedona/common/utils/GeometrySplitter.java
@@ -262,13 +262,9 @@ private void splitOnCoord(LinearGeometryBuilder lineBuilder, Coordinate coord) {
   }
 
   private Geometry generateCandidatePolygons(Geometry polygons, Geometry blade) {
-    // restrict the blade to only be within the original polygon to
-    // avoid candidate polygons that are impossible
-    Geometry bladeWithinPolygons = blade.intersection(polygons);
-
     // a union will node all the lines at intersections
     // these nodes are required for Polygonizer to work correctly
-    Geometry totalLineWork = polygons.getBoundary().union(bladeWithinPolygons);
+    Geometry totalLineWork = polygons.getBoundary().union(blade);
 
     Polygonizer polygonizer = new Polygonizer();
     polygonizer.add(totalLineWork);
@@ -281,7 +277,18 @@ private void addValidPolygonsToList(Geometry polygons, Geometry original, List<P
     // original geometry to ensure holes in the original geometry are excluded
     for (int i = 0; i < polygons.getNumGeometries(); i++) {
       Geometry candidateResult = polygons.getGeometryN(i);
-      if (candidateResult instanceof Polygon && original.contains(candidateResult)) {
+      if (!(candidateResult instanceof Polygon)) {
+        continue;
+      }
+
+      Point pointOnSurface = candidateResult.getInteriorPoint();
+      // getInteriorPoint() may return null for degenerate or empty polygonal geometries,
+      // so guard against null before using the point.
+      if (pointOnSurface == null) {
+        continue;
+      }
+
+      if (original.covers(pointOnSurface)) {
         list.add((Polygon) candidateResult);
       }
     }
diff --git a/common/src/test/java/org/apache/sedona/common/FunctionsTest.java b/common/src/test/java/org/apache/sedona/common/FunctionsTest.java
index c5eac14c390..0ff5b2503e5 100644
--- a/common/src/test/java/org/apache/sedona/common/FunctionsTest.java
+++ b/common/src/test/java/org/apache/sedona/common/FunctionsTest.java
@@ -24,6 +24,8 @@
 
 import com.google.common.geometry.S2CellId;
 import com.google.common.math.DoubleMath;
+import java.io.IOException;
+import java.io.InputStream;
 import java.util.*;
 import java.util.stream.Collectors;
 import org.apache.sedona.common.sphere.Haversine;
@@ -62,6 +64,15 @@ protected int compareCoordinate(
         }
       };
 
+  private static String readResourceString(String resourcePath) throws IOException {
+    try (InputStream inputStream = FunctionsTest.class.getResourceAsStream(resourcePath)) {
+      if (inputStream == null) {
+        throw new IllegalArgumentException("Resource not found: " + resourcePath);
+      }
+      return new String(inputStream.readAllBytes(), java.nio.charset.StandardCharsets.UTF_8).trim();
+    }
+  }
+
   private final WKTReader wktReader = new WKTReader();
 
   @Test
@@ -531,6 +542,36 @@ public void splitHeterogeneousGeometryCollection() {
     assertNull(actualResult);
   }
 
+  @Test
+  public void splitCircleInto2SemiCircles() throws ParseException, IOException {
+    String polygonWkt =
+        "POLYGON ((-117.76405581088967 34.111876749328026, -117.76407506132291 34.11170068822483, "
+            + "-117.76413523652074 34.111531133837936, -117.76423402376724 34.11137460199335, -117.76436762657538 34.11123710803779, "
+            + "-117.76453091060647 34.11112393568514, -117.76471760098879 34.11103943398174, -117.76492052345083 34.11098685019075, "
+            + "-117.76513188000408 34.1109682050154, -117.76534354858369 34.11098421495394, -117.76554739513688 34.11103426476887, "
+            + "-117.76573558617179 34.11111643112786, -117.76590088976099 34.111227556508084, -117.76603695343799 34.11136337052523, "
+            + "-117.76613854831002 34.11151865402651, -117.76620177000793 34.11168743964393, -117.76622418874936 34.111863241103265, "
+            + "-117.76620494274577 34.11203930247842, -117.76614477135817 34.11220885781403, -117.7660459867224 34.11236539113964, "
+            + "-117.76591238492807 34.11250288688306, -117.7657491001595 34.11261606105824, -117.7655624074007 34.11270056434135, "
+            + "-117.76535948128496 34.112753149228745, -117.76514812035703 34.11277179485027, -117.76493644734776 34.112755784639766, "
+            + "-117.76473259698435 34.112705733876126, -117.76454440333869 34.11262356603611, -117.76437909873567 34.11251243886801, "
+            + "-117.76424303579616 34.11237662302835, -117.76414144330062 34.112221337947354, -117.76407822525644 34.11205255123353, "
+            + "-117.76405581088967 34.111876749328026))";
+    String knifeWkt =
+        "LINESTRING (-117.7640751398563 34.111535124121441, -117.76628486838135 34.112204866513046)";
+
+    Geometry polygon = Constructors.geomFromWKT(polygonWkt, 4326);
+    Geometry knife = Constructors.geomFromWKT(knifeWkt, 4326);
+    Geometry resultPolygon = Functions.split(polygon, knife);
+    assertEquals(2, resultPolygon.getNumGeometries());
+
+    double circleArea = polygon.getArea();
+    for (int i = 0; i < resultPolygon.getNumGeometries(); i++) {
+      double actualArea = resultPolygon.getGeometryN(i).getArea();
+      assertEquals(2.0, circleArea / actualArea, 0.1);
+    }
+  }
+
   @Test
   public void dimensionGeometry2D() {
     Point point = GEOMETRY_FACTORY.createPoint(new Coordinate(1, 2));

From 9d1c866fd8d7119d798e7ad1b9ed216753ac1d34 Mon Sep 17 00:00:00 2001
From: Kristin Cowalcijk <bo@wherobots.com>
Date: Thu, 22 Jan 2026 09:02:05 +0800
Subject: [PATCH 2/2] Remove unnecessary function

---
 .../org/apache/sedona/common/FunctionsTest.java     | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/common/src/test/java/org/apache/sedona/common/FunctionsTest.java b/common/src/test/java/org/apache/sedona/common/FunctionsTest.java
index 0ff5b2503e5..c4e63251437 100644
--- a/common/src/test/java/org/apache/sedona/common/FunctionsTest.java
+++ b/common/src/test/java/org/apache/sedona/common/FunctionsTest.java
@@ -24,8 +24,6 @@
 
 import com.google.common.geometry.S2CellId;
 import com.google.common.math.DoubleMath;
-import java.io.IOException;
-import java.io.InputStream;
 import java.util.*;
 import java.util.stream.Collectors;
 import org.apache.sedona.common.sphere.Haversine;
@@ -64,15 +62,6 @@ protected int compareCoordinate(
         }
       };
 
-  private static String readResourceString(String resourcePath) throws IOException {
-    try (InputStream inputStream = FunctionsTest.class.getResourceAsStream(resourcePath)) {
-      if (inputStream == null) {
-        throw new IllegalArgumentException("Resource not found: " + resourcePath);
-      }
-      return new String(inputStream.readAllBytes(), java.nio.charset.StandardCharsets.UTF_8).trim();
-    }
-  }
-
   private final WKTReader wktReader = new WKTReader();
 
   @Test
@@ -543,7 +532,7 @@ public void splitHeterogeneousGeometryCollection() {
   }
 
   @Test
-  public void splitCircleInto2SemiCircles() throws ParseException, IOException {
+  public void splitCircleInto2SemiCircles() throws ParseException {
     String polygonWkt =
         "POLYGON ((-117.76405581088967 34.111876749328026, -117.76407506132291 34.11170068822483, "
             + "-117.76413523652074 34.111531133837936, -117.76423402376724 34.11137460199335, -117.76436762657538 34.11123710803779, "