--- a/src/Grids/mapped_grid.jl	Thu Apr 25 14:37:59 2024 +0200
+++ b/src/Grids/mapped_grid.jl	Thu Apr 25 14:38:15 2024 +0200
@@ -61,6 +61,15 @@
     )
 end
 
+function mapped_grid(c::Chart, size...)
+    lg = equidistant_grid(parameterspace(c), size...)
+    return MappedGrid(
+        lg,
+        map(c,lg),
+        map(jacobian(c), lg),
+    )
+end
+
 function jacobian_determinant(g::MappedGrid)
     return map(jacobian(g)) do ∂x∂ξ
         det(∂x∂ξ)

--- a/test/Grids/mapped_grid_test.jl	Thu Apr 25 14:37:59 2024 +0200
+++ b/test/Grids/mapped_grid_test.jl	Thu Apr 25 14:38:15 2024 +0200
@@ -185,12 +185,13 @@
     @test collect(mg) == map(x̄, lg)
 
 
-    @testset "mapped_grid(::Chart,J)" begin
-        c = ConcreteChart(unitsquare()) do (x,y)
-            @SVector[2x, 3y]
+    @testset "mapped_grid(::Chart)" begin
+        c = ConcreteChart(unitsquare()) do (ξ,η)
+            @SVector[2ξ, 3η]
         end
+        Grids.jacobian(c::typeof(c)) = x̄ -> @SMatrix[2 0; 0 3] ## TODO Maybe shouldn't return a function
 
-        @test mapped_grid(c, 5, 4)
+        @test mapped_grid(c, 5, 4) isa Grid
     end
 
 end