diff --git a/src/cubes.jl b/src/cubes.jl
index 16e1d11..910c7ae 100644
--- a/src/cubes.jl
+++ b/src/cubes.jl
@@ -94,7 +94,9 @@ function query(cell_cube::CellCube, query_str::String="all")
     return CellCube(data, cell_cube.level)
 end
 
-function reduce(agg_func, cell_cube::CellCube; dims)
+function Base.mapslices(agg_func, cell_cube::CellCube; dims, kw...)
+    data = mapslices(agg_func, cell_cube.data; dims, kw...)
+    return CellCube(data, cell_cube.level)
 end
 
 "maximial i or j value in Q2DI index given a level"
diff --git a/src/gridsystems.jl b/src/gridsystems.jl
index 6db5327..20e2620 100644
--- a/src/gridsystems.jl
+++ b/src/gridsystems.jl
@@ -99,4 +99,9 @@ Base.getindex(dggs::GridSystem, level::Int) = dggs.data[level]
 Base.setindex!(dggs::GridSystem, cell_cube::CellCube, level::Int) = dggs.data[level] = cell_cube
 
 CellCube(dggs::GridSystem) = dggs[dggs.data|>keys|>maximum]
-plot(dggs::GridSystem) = dggs |> CellCube |> plot
\ No newline at end of file
+plot(dggs::GridSystem) = dggs |> CellCube |> plot
+
+function Base.mapslices(f, dggs::GridSystem; dims, kw...)
+    data = dggs |> CellCube |> x -> mapslices(f, x; dims=dims, kw...)
+    return GridSystem(data)
+end
\ No newline at end of file
diff --git a/src/types.jl b/src/types.jl
index c4e208f..863ea84 100644
--- a/src/types.jl
+++ b/src/types.jl
@@ -13,6 +13,15 @@ end
 struct CellCube
     data::YAXArray
     level::Int8
+
+    function CellCube(data, level)
+        level > 0 || error("Level must be positive")
+        :q2di_i in name.(data.axes) || error("Axis q2di_i is missing")
+        :q2di_j in name.(data.axes) || error("Axis q2di_j is missing")
+        :q2di_n in name.(data.axes) || error("Axis q2di_n is missing")
+
+        new(data, level)
+    end
 end
 
 struct GeoCube
diff --git a/test/runtests.jl b/test/runtests.jl
index a703107..b43aad5 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,6 +1,6 @@
 using DGGS
 using Test
-
+using Statistics
 
 @testset verbose = true "DGGS.jl" begin
     lon_range = -180:180
@@ -18,6 +18,9 @@ using Test
     @test geo_cube |> x -> CellCube(x, 8) |> GeoCube |> typeof == GeoCube
     @test keys(dggs.data) |> maximum == 6
 
+    @test_throws ErrorException mapslices(mean, dggs[6]; dims=["q2di_i", "q2di_j"])
+    @test
+
     dggs_path = tempname()
     write(dggs_path, dggs)
     dggs2 = GridSystem(dggs_path)