diff --git a/base_geoengine/fields.py b/base_geoengine/fields.py
index ef8ebc4608..f0d8beedbf 100644
--- a/base_geoengine/fields.py
+++ b/base_geoengine/fields.py
@@ -30,7 +30,7 @@ class GeoField(fields.Field):
     """
 
     geo_type = None
-    dim = 2
+    dim = "2"
     srid = 3857
     gist_index = True