diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index 586ad20938d..c3ff48284b5 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -227,7 +227,10 @@ Bug fixes:
   shape tessellation. (Ignacio Vera)
 
 * LUCENE-8559: Fix bug where polygon edges were skipped when checking for intersections.
-  (Ignacio Vera)   
+  (Ignacio Vera)
+
+* LUCENE-8556: Use latitude and longitude instead of encoding values to check if triangle is ear
+  when using morton optimisation. (Ignacio Vera)
 
 New Features
 
diff --git a/lucene/sandbox/src/java/org/apache/lucene/geo/Tessellator.java b/lucene/sandbox/src/java/org/apache/lucene/geo/Tessellator.java
index 8fa685ce7e3..1fa044360bd 100644
--- a/lucene/sandbox/src/java/org/apache/lucene/geo/Tessellator.java
+++ b/lucene/sandbox/src/java/org/apache/lucene/geo/Tessellator.java
@@ -353,13 +353,6 @@ final public class Tessellator {
 
   /** Uses morton code for speed to determine whether or a polygon node forms a valid ear w/ adjacent nodes */
   private static final boolean mortonIsEar(final Node ear) {
-    double ax = ear.previous.x;
-    double ay = ear.previous.y;
-    double bx = ear.x;
-    double by = ear.y;
-    double cx = ear.next.x;
-    double cy = ear.next.y;
-
     // triangle bbox (flip the bits so negative encoded values are < positive encoded values)
     int minTX = StrictMath.min(StrictMath.min(ear.previous.x, ear.x), ear.next.x) ^ 0x80000000;
     int minTY = StrictMath.min(StrictMath.min(ear.previous.y, ear.y), ear.next.y) ^ 0x80000000;
@@ -378,21 +371,21 @@ final public class Tessellator {
     while (p != null && Long.compareUnsigned(p.morton, minZ) >= 0
         && n != null && Long.compareUnsigned(n.morton, maxZ) <= 0) {
       if (p.idx != ear.previous.idx && p.idx != ear.next.idx &&
-          pointInEar(p.x, p.y, ax, ay, bx, by, cx, cy) &&
-          area(p.previous.x, p.previous.y, p.x, p.y, p.next.x, p.next.y) >= 0) return false;
+          pointInEar(p.getX(), p.getY(), ear.previous.getX(), ear.previous.getY(), ear.getX(), ear.getY(), ear.next.getX(), ear.next.getY()) &&
+          area(p.previous.getX(), p.previous.getY(), p.getX(), p.getY(), p.next.getX(), p.next.getY()) >= 0) return false;
       p = p.previousZ;
 
       if (n.idx != ear.previous.idx && n.idx != ear.next.idx &&
-          pointInEar(n.x, n.y, ax, ay, bx, by, cx, cy) &&
-          area(n.previous.x, n.previous.y, n.x, n.y, n.next.x, n.next.y) >= 0) return false;
+          pointInEar(n.getX(), n.getY(), ear.previous.getX(), ear.previous.getY(), ear.getX(), ear.getY(), ear.next.getX(), ear.next.getY()) &&
+          area(n.previous.getX(), n.previous.getY(), n.getX(), n.getY(), n.next.getX(), n.next.getY()) >= 0) return false;
       n = n.nextZ;
     }
 
     // first look for points inside the triangle in decreasing z-order
     while (p != null && Long.compareUnsigned(p.morton, minZ) >= 0) {
       if (p.idx != ear.previous.idx && p.idx != ear.next.idx
-            && pointInEar(p.x, p.y, ax, ay, bx, by, cx, cy)
-            && area(p.previous.x, p.previous.y, p.x, p.y, p.next.x, p.next.y) >= 0) {
+            && pointInEar(p.getX(), p.getY(), ear.previous.getX(), ear.previous.getY(), ear.getX(), ear.getY(), ear.next.getX(), ear.next.getY())
+            && area(p.previous.getX(), p.previous.getY(), p.getX(), p.getY(), p.next.getX(), p.next.getY()) >= 0) {
           return false;
         }
       p = p.previousZ;
@@ -401,8 +394,8 @@ final public class Tessellator {
     while (n != null &&
         Long.compareUnsigned(n.morton, maxZ) <= 0) {
         if (n.idx != ear.previous.idx && n.idx != ear.next.idx
-            && pointInEar(n.x, n.y, ax, ay, bx, by, cx, cy)
-            && area(n.previous.x, n.previous.y, n.x, n.y, n.next.x, n.next.y) >= 0) {
+            && pointInEar(n.getX(), n.getY(), ear.previous.getX(), ear.previous.getY(), ear.getX(), ear.getY(), ear.next.getX(), ear.next.getY())
+            && area(n.previous.getX(), n.previous.getY(), n.getX(), n.getY(), n.next.getX(), n.next.getY()) >= 0) {
           return false;
         }
       n = n.nextZ;
diff --git a/lucene/sandbox/src/test/org/apache/lucene/geo/TestTessellator.java b/lucene/sandbox/src/test/org/apache/lucene/geo/TestTessellator.java
index 7904725d9a3..d5b7e664237 100644
--- a/lucene/sandbox/src/test/org/apache/lucene/geo/TestTessellator.java
+++ b/lucene/sandbox/src/test/org/apache/lucene/geo/TestTessellator.java
@@ -103,4 +103,18 @@ public class TestTessellator extends LuceneTestCase {
     Polygon polygon = (Polygon)SimpleWKTShapeParser.parse(wkt);
     assertTrue(Tessellator.tessellate(polygon).size() > 0);
   }
+
+  public void testLUCENE8556()  throws Exception {
+    String wkt ="POLYGON((-111.4765 68.321,-111.47625 68.32225,-111.4765 68.3225,-111.478 68.3225,-111.47825 68.32275,-111.479 68.32275,-111.47975 68.32325,-111.48125 68.324,-111.4815 68.32375,-111.48175 68.32375," +
+        "-111.48225 68.32425,-111.48275 68.32425,-111.483 68.324,-111.4845 68.324,-111.48475 68.32425,-111.4845 68.32475,-111.48425 68.3245,-111.483 68.325,-111.4835 68.325,-111.48425 68.3255,-111.48525 68.3255,-111.4855 68.32575," +
+        "-111.4855 68.32525,-111.486 68.32475,-111.48725 68.3245,-111.4875 68.32475,-111.48725 68.325,-111.487 68.325,-111.4865 68.32525,-111.487 68.32575,-111.486465 68.326385,-111.486 68.326,-111.48575 68.32625," +
+        "-111.48525 68.32625,-111.485 68.326,-111.48375 68.326,-111.48225 68.3265,-111.483 68.3265,-111.48325 68.32675,-111.4835 68.3265,-111.48675 68.3265,-111.487 68.32675,-111.48675 68.32725,-111.4865 68.327," +
+        "-111.48375 68.32775,-111.485 68.32775,-111.48525 68.3275,-111.4855 68.3275,-111.486 68.32775,-111.48625 68.3275,-111.48675 68.3275,-111.48725 68.327,-111.48775 68.327,-111.4875 68.32625,-111.488 68.32625," +
+        "-111.48825 68.32675,-111.49025 68.327,-111.49025 68.32675,-111.4905 68.3265,-111.49075 68.3265,-111.49125 68.326,-111.492 68.32575,-111.4945 68.32575,-111.49475 68.3255,-111.49525 68.3255,-111.4955 68.32525,-111.49625 68.32525," +
+        "-111.4965 68.325,-111.49775 68.32425,-111.498 68.3245,-111.4985 68.3245,-111.49875 68.32425,-111.49925 68.32425,-111.5005 68.324,-111.50075 68.32375,-111.501 68.32375,-111.501 68.323,-111.5015 68.323,-111.50175 68.32325,-111.5015 68.3235," +
+        "-111.5025 68.32375,-111.50275 68.3235,-111.504 68.32375,-111.50425 68.3235,-111.50525 68.32325,-111.5055 68.3235,-111.506 68.3235,-111.50625 68.32325,-111.5065 68.3225,-111.5075 68.3225,-111.50775 68.32275,-111.50825 68.32275," +
+        "-111.5085 68.3225,-111.50875 68.3225,-111.509 68.32275,-111.5125 68.32275,-111.51325 68.32225,-111.4765 68.321))";
+    Polygon polygon = (Polygon) SimpleWKTShapeParser.parse(wkt);
+    assertTrue(Tessellator.tessellate(polygon).size() > 0);
+  }
 }
\ No newline at end of file