From bf71d665ee7ea2f019d97f5653b26f5787474325 Mon Sep 17 00:00:00 2001
From: Martin Davis <mtnclimb@gmail.com>
Date: Mon, 29 Jul 2024 15:52:29 -0700
Subject: [PATCH] Fix RelateNG handling of empty point elements

---
 .../operation/relateng/RelateGeometry.java    |  2 ++
 .../operation/relateng/RelateNGGCTest.java    |  6 ++++++
 .../resources/testxml/misc/TestRelateGC.xml   | 21 +++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateGeometry.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateGeometry.java
index 9f5ac3cd03..7bc7bf8503 100644
--- a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateGeometry.java
+++ b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateGeometry.java
@@ -295,6 +295,8 @@ public List<Point> getEffectivePoints() {
     //-- only return Points not covered by another element
     List<Point> ptList = new ArrayList<Point>();
     for (Point p : ptListAll) {
+      if (p.isEmpty())
+        continue;
       int locDim = locateWithDim(p.getCoordinate());
       if (DimensionLocation.dimension(locDim) == Dimension.P) {
         ptList.add(p);
diff --git a/modules/core/src/test/java/org/locationtech/jts/operation/relateng/RelateNGGCTest.java b/modules/core/src/test/java/org/locationtech/jts/operation/relateng/RelateNGGCTest.java
index 140708bf91..b63193f174 100644
--- a/modules/core/src/test/java/org/locationtech/jts/operation/relateng/RelateNGGCTest.java
+++ b/modules/core/src/test/java/org/locationtech/jts/operation/relateng/RelateNGGCTest.java
@@ -208,5 +208,11 @@ public void testAdjPolygonsContainingLineAndPoint() {
     checkCoversCoveredBy(a, b, true);
   }
   
+  public void testEmptyMultiPointElements() {
+    String a = "POLYGON ((3 7, 7 7, 7 3, 3 3, 3 7))";
+    String b = "GEOMETRYCOLLECTION (MULTIPOINT (EMPTY, (5 5)), LINESTRING (1 9, 4 9))";
+    checkIntersectsDisjoint(a, b, true);
+  }
+  
 
 }
diff --git a/modules/tests/src/test/resources/testxml/misc/TestRelateGC.xml b/modules/tests/src/test/resources/testxml/misc/TestRelateGC.xml
index 8eec76e4bc..3b23304a93 100644
--- a/modules/tests/src/test/resources/testxml/misc/TestRelateGC.xml
+++ b/modules/tests/src/test/resources/testxml/misc/TestRelateGC.xml
@@ -42,6 +42,27 @@
   <test><op name="within"     arg1="A" arg2="B"> false </op></test>
 </case>
 
+<case>
+  <desc>A/GC:mP with empty MultiPoint elements</desc>
+  <a>
+    POLYGON ((3 7, 7 7, 7 3, 3 3, 3 7))
+  </a>
+  <b>
+    GEOMETRYCOLLECTION (MULTIPOINT (EMPTY, (5 5)), LINESTRING (1 9, 4 9))
+  </b>
+  <test><op name="relate" arg3="0F2FF1102" arg1="A" arg2="B"> true </op></test>
+  <test><op name="contains"   arg1="A" arg2="B"> false </op></test>
+  <test><op name="coveredBy"  arg1="A" arg2="B"> false </op></test>
+  <test><op name="covers"     arg1="A" arg2="B"> false </op></test>
+  <test><op name="crosses"    arg1="A" arg2="B"> true </op></test>
+  <test><op name="disjoint"   arg1="A" arg2="B"> false </op></test>
+  <test><op name="equalsTopo" arg1="A" arg2="B"> false </op></test>
+  <test><op name="intersects" arg1="A" arg2="B"> true </op></test>
+  <test><op name="overlaps"   arg1="A" arg2="B"> false </op></test>
+  <test><op name="touches"    arg1="A" arg2="B"> false </op></test>
+  <test><op name="within"     arg1="A" arg2="B"> false </op></test>
+</case>
+
 <case>
   <desc>mA/GC:PL</desc>
   <a>