--- a/src/Grids/manifolds.jl	Fri Apr 25 08:28:34 2025 +0200
+++ b/src/Grids/manifolds.jl	Fri Apr 25 16:05:58 2025 +0200
@@ -36,7 +36,12 @@
 ```
 which will both allow calling `jacobian(c,ξ)`.
 """
-jacobian(c::Chart, ξ) = jacobian(c.mapping, ξ)
+function jacobian(c::Chart, ξ)
+    if ξ ∉ parameterspace(c)
+        throw(DomainError(ξ, "jacobian was called with logical coordinates outside the parameterspace of the chart. If this was inteded, use the `mapping` field from the Chart struct instead."))
+    end
+    return jacobian(c.mapping, ξ)
+end
 
 boundary_identifiers(c::Chart) = boundary_identifiers(parameterspace(c))
 

--- a/test/Grids/manifolds_test.jl	Fri Apr 25 08:28:34 2025 +0200
+++ b/test/Grids/manifolds_test.jl	Fri Apr 25 16:05:58 2025 +0200
@@ -15,7 +15,7 @@
 
 @testset "Chart" begin
     X(ξ) = 2ξ
-    Grids.jacobian(::typeof(X), ξ) = @SVector[2,2]
+    Grids.jacobian(::typeof(X), ξ) = @SMatrix[2 0; 0 2]
     c = Chart(X, unitsquare())
     @test c isa Chart{2}
     @test parameterspace(c) == unitsquare()
@@ -27,7 +27,11 @@
         @test_throws DomainError c([3,2])
     end
 
-    @test jacobian(c, [3,2]) == [2,2]
+    @testset "jacobian(::Chart, ⋅)" begin
+        c = Chart(X, unitsquare())
+        @test_throws DomainError jacobian(c, [3,2])
+        @test jacobian(c, [.3,.2]) == [2 0; 0 2]
+    end
 
     @test Set(boundary_identifiers(Chart(X,unitsquare()))) == Set([east(),west(),south(),north()])
 end