diff --git a/src/nc_dim.jl b/src/nc_dim.jl
index 8d21c48..2381474 100644
--- a/src/nc_dim.jl
+++ b/src/nc_dim.jl
@@ -120,8 +120,8 @@ end
     nc_cellsize(ds::NCdata)
 """
 function nc_cellsize(ds::NCdata)
-  diflon = nc_dim(ds, "lon").vals |> diff
-  diflat = nc_dim(ds, "lat").vals |> diff
+  diflon = nc_dim(ds, r"lon").vals |> diff
+  diflat = nc_dim(ds, r"lat").vals |> diff
 
   cell_x = mode(diflon)
   cell_y = mode(diflat)