diff --git a/src/schema/Feature.js b/src/schema/Feature.js
index 5fb826c..587c314 100644
--- a/src/schema/Feature.js
+++ b/src/schema/Feature.js
@@ -20,7 +20,13 @@ export default {
       oneOf: [{type: 'number'}, {type: 'string'}],
     },
     properties: {
-      oneOf: [{type: 'null'}, {type: 'object'}],
+      type: 'object',
+      required: ['path_class_name'],
+      properties: {
+        path_class_name: {
+          type: 'string',
+        },
+      },
     },
     geometry: {
       oneOf: [
diff --git a/src/schema/FeatureCollection.js b/src/schema/FeatureCollection.js
index 53b3cfe..20a0cff 100644
--- a/src/schema/FeatureCollection.js
+++ b/src/schema/FeatureCollection.js
@@ -4,7 +4,7 @@ import Feature from './Feature.js';
 export default {
   title: 'GeoJSON FeatureCollection',
   type: 'object',
-  required: ['type', 'features'],
+  required: ['type', 'features', 'ontology_link', 'ontology_id'],
   properties: {
     type: {
       type: 'string',
@@ -15,5 +15,11 @@ export default {
       items: Feature,
     },
     bbox: BoundingBox,
+    ontology_link: {
+      type: 'string',
+    },
+    ontology_id: {
+      type: 'string',
+    },
   },
 };
diff --git a/src/schema/ontology.js b/src/schema/ontology.js
new file mode 100644
index 0000000..c7207af
--- /dev/null
+++ b/src/schema/ontology.js
@@ -0,0 +1,23 @@
+export default {
+    title: 'JSON Ontology',
+    type: 'object',
+    // As we do not know key names in advance we cannot use `properties`
+    additionalProperties: {
+      type: 'array',
+      items: {
+        type: 'object',
+        required: ['type', 'color'],
+        properties: {
+          type: {
+            type: 'string',
+          },
+          color: {
+            type: 'string',
+            pattern: '^#[0-9A-Fa-f]{6}$', // Ensure color is a valid hex code
+          },
+        },
+        additionalProperties: false, // No additional properties allowed within objects
+      },
+    },
+  };
+  
\ No newline at end of file