diff --git a/buildings-figure-ground.json b/buildings-figure-ground.json
new file mode 100644
index 00000000..63d23c7e
--- /dev/null
+++ b/buildings-figure-ground.json
@@ -0,0 +1,37 @@
+{
+    "type": "overpass",
+    "name": {
+        "de": "Schwarzplan",
+        "en": "Figure-ground diagram"
+    },
+    "query": {
+        "16": [
+            "(",
+            "  way[building];",
+            "  relation[building];",
+            ")"
+        ]
+    },
+    "feature": {
+        "markerSymbol": null,
+        "priority": [
+            "{% set p = 100 %}",
+            "{% if tags.name %}{% set p = p - 10 %}{% endif %}",
+            "{% if tags.amenity %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.historic %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.culture %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.highway %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.railway %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.aeroway %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.amenity %}{% set p = p - 1 %}{% endif %}",
+            "{% if tags.tourism %}{% set p = p - 1 %}{% endif %}",
+            "{{ p }}"
+        ],
+        "style": {
+            "width": "0",
+            "color": "#000000",
+            "fillColor": "#000000",
+            "fillOpacity": "1"
+        }
+    }
+}
diff --git a/buildings.json b/buildings.json
index 17b49fa7..94bb4a9a 100644
--- a/buildings.json
+++ b/buildings.json
@@ -1,38 +1,14 @@
 {
-    "type": "overpass",
+    "type": "index",
     "name": {
         "de": "Gebäude",
         "en": "Buildings",
         "fr": "Bâtiments",
         "pt-br": "Edificações"
     },
-    "query": {
-        "16": [
-            "(",
-            "  way[building];",
-            "  relation[building];",
-            ")"
-        ]
-    },
-    "feature": {
-        "markerSymbol": null,
-        "priority": [
-            "{% set p = 100 %}",
-            "{% if tags.name %}{% set p = p - 10 %}{% endif %}",
-            "{% if tags.amenity %}{% set p = p - 1 %}{% endif %}",
-            "{% if tags.historic %}{% set p = p - 1 %}{% endif %}",
-            "{% if tags.culture %}{% set p = p - 1 %}{% endif %}",
-            "{% if tags.highway %}{% set p = p - 1 %}{% endif %}",
-            "{% if tags.railway %}{% set p = p - 1 %}{% endif %}",
-            "{% if tags.aeroway %}{% set p = p - 1 %}{% endif %}",
-            "{% if tags.amenity %}{% set p = p - 1 %}{% endif %}",
-            "{% if tags.tourism %}{% set p = p - 1 %}{% endif %}",
-            "{{ p }}"
-        ],
-        "style": {
-            "width": "1",
-            "color": "#000000",
-            "fillColor": "#000000"
+    "subCategories": [
+        {
+            "id": "buildings-figure-ground"
         }
-    }
+    ]
 }