diff --git a/src/c3nav/mapdata/schemas/model_base.py b/src/c3nav/mapdata/schemas/model_base.py
index c26cac2a..4039cb44 100644
--- a/src/c3nav/mapdata/schemas/model_base.py
+++ b/src/c3nav/mapdata/schemas/model_base.py
@@ -340,7 +340,7 @@ class SimpleGeometryLocationsSchema(BaseSchema):
 
 CustomLocationID = Annotated[NonEmptyStr, APIField(
     title="custom location ID",
-    pattern=r"c:[a-z0-9-_]+:(-?\d+(\.\d+)?):(-?\d+(\.\d+)?)$",
+    pattern=r"c:[a-z0-9-_.]+:(-?\d+(\.\d+)?):(-?\d+(\.\d+)?)$",
     example="c:0:-7.23:12.34",
     description="level short_name and x/y coordinates form the ID of a custom location"
 )]
diff --git a/src/c3nav/mapdata/utils/locations.py b/src/c3nav/mapdata/utils/locations.py
index bea34a56..ed8c013d 100644
--- a/src/c3nav/mapdata/utils/locations.py
+++ b/src/c3nav/mapdata/utils/locations.py
@@ -291,7 +291,7 @@ class CustomLocation:
     def __post_init__(self):
         x = round(self.x, 2)
         y = round(self.y, 2)
-        self.pk = 'c:%s:%s:%s' % (self.level.short_label, x, y)
+        self.pk = 'c:%s:%s:%s' % (self.level.level_index, x, y)
 
     @property
     def serialized_geometry(self):