Change RelateNG semantics so all EMPTY geometries are topologically e…

…qual (#1089)
locationtech · Oct 11, 2024 · 13ea27e · 13ea27e
1 parent 7ff3367
commit 13ea27e
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Showing 3 changed files with 13 additions and 9 deletions.
diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateNG.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelateNG.java
@@ -227,10 +227,6 @@ public boolean evaluate(Geometry b, TopologyPredicate predicate) {
 
     RelateGeometry geomB = new RelateGeometry(b, boundaryNodeRule);
 
-    if (geomA.isEmpty() && geomB.isEmpty()) {
-      //TODO: what if predicate is disjoint?  Perhaps use result on disjoint envs?
-      return finishValue(predicate);
-    }
     int dimA = geomA.getDimensionReal();
     int dimB = geomB.getDimensionReal();
 

diff --git a/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelatePredicate.java b/modules/core/src/main/java/org/locationtech/jts/operation/relateng/RelatePredicate.java
@@ -482,11 +482,20 @@ public static TopologyPredicate equalsTopo() {
       @Override
       public void init(int dimA, int dimB) {
         super.init(dimA, dimB);
-        require(dimA == dimB);
+        //-- don't require equal dims, because EMPTY = EMPTY for all dims
       }
 
+      @Override
+      public boolean requireInteraction() {
+        //-- allow EMPTY = EMPTY
+        return false;
+      };
+
       @Override
       public void init(Envelope envA, Envelope envB) {
+        //-- handle EMPTY = EMPTY cases
+        setValueIf(true, envA.isNull() && envB.isNull());
+
         require(envA.equals(envB));
       }   
 

diff --git a/modules/core/src/test/java/org/locationtech/jts/operation/relateng/RelateNGTest.java b/modules/core/src/test/java/org/locationtech/jts/operation/relateng/RelateNGTest.java
@@ -597,7 +597,7 @@ public void testRepeatedPointAA() {
     checkRelate(a, b, "212F01FF2");
   }
 
-  //================  Repeated Points  ==============
+  //================  EMPTY geometries  ==============
 
   public void testEmptyEquals() {
     String empties[] = {
@@ -614,9 +614,8 @@ public void testEmptyEquals() {
       for (int j = 0; j < nempty; j++) {
         String a = empties[i];
         String b = empties[j];
-        checkRelate(a, b, "FFFFFFFF2");
-        //-- currently in JTS empty geometries do NOT test equal
-         checkEquals(a, b, false);
+        ///-- empty geometries are all topologically equal
+        checkEquals(a, b, true);
       }
     }  
   }