diff --git a/Domains/4-Application/OpenSite/OpenSite.ecschema.xml b/Domains/4-Application/OpenSite/OpenSite.ecschema.xml
index a53ac7b9d..4bd03a310 100644
--- a/Domains/4-Application/OpenSite/OpenSite.ecschema.xml
+++ b/Domains/4-Application/OpenSite/OpenSite.ecschema.xml
@@ -142,6 +142,16 @@
         </Target>
     </ECRelationshipClass>
 
+    <ECRelationshipClass typeName="CenterlineCategorySymbolizesClassification" strength="referencing" modifier="Sealed">
+        <BaseClass>CategorySymbolizesClassification</BaseClass>
+        <Source multiplicity="(0..1)" roleLabel="symbolizes" polymorphic="true">
+            <Class class="bis:Category" />
+        </Source>
+        <Target multiplicity="(0..*)" roleLabel="is symbolized by" polymorphic="false">
+            <Class class="clsf:Classification" />
+        </Target>
+    </ECRelationshipClass>
+
     <ECRelationshipClass typeName="GradingLimitCategorySymbolizesClassification" strength="referencing" modifier="Sealed">
         <BaseClass>CategorySymbolizesClassification</BaseClass>
         <Source multiplicity="(0..1)" roleLabel="symbolizes" polymorphic="true">