diff --git a/docs/blog/posts/isq-part-3-modeling-isq.md b/docs/blog/posts/isq-part-3-modeling-isq.md
index a2ed0864..58e21107 100644
--- a/docs/blog/posts/isq-part-3-modeling-isq.md
+++ b/docs/blog/posts/isq-part-3-modeling-isq.md
@@ -150,8 +150,8 @@ flowchart TD
     path_length --- distance["<b>distance</b>"]
     distance --- radial_distance["<b>radial_distance</b>"]
     length --- wavelength["<b>wavelength</b>"]
-    length --- position_vector["<b>position_vector</b><br>{vector}"]
     length --- displacement["<b>displacement</b><br>{vector}"]
+    displacement --- position_vector["<b>position_vector</b>"]
     radius --- radius_of_curvature["<b>radius_of_curvature</b>"]
 ```
 
diff --git a/docs/blog/posts/isq-part-4-implemeting-isq.md b/docs/blog/posts/isq-part-4-implemeting-isq.md
index aff8f285..61dca347 100644
--- a/docs/blog/posts/isq-part-4-implemeting-isq.md
+++ b/docs/blog/posts/isq-part-4-implemeting-isq.md
@@ -49,8 +49,8 @@ flowchart TD
     path_length --- distance["<b>distance</b>"]
     distance --- radial_distance["<b>radial_distance</b>"]
     length --- wavelength["<b>wavelength</b>"]
-    length --- position_vector["<b>position_vector</b><br>{vector}"]
     length --- displacement["<b>displacement</b><br>{vector}"]
+    displacement --- position_vector["<b>position_vector</b>"]
     radius --- radius_of_curvature["<b>radius_of_curvature</b>"]
 ```
 
@@ -74,8 +74,8 @@ inline constexpr auto arc_length = path_length;
 inline constexpr struct distance final            : quantity_spec<path_length> {} distance;
 inline constexpr struct radial_distance final     : quantity_spec<distance> {} radial_distance;
 inline constexpr struct wavelength final          : quantity_spec<length> {} wavelength;
-inline constexpr struct position_vector final     : quantity_spec<length, quantity_character::vector> {} position_vector;
 inline constexpr struct displacement final        : quantity_spec<length, quantity_character::vector> {} displacement;
+inline constexpr struct position_vector final     : quantity_spec<displacement> {} position_vector;
 ```
 
 Thanks to the expressivity and power of C++ templates, we can specify all quantity properties
diff --git a/docs/users_guide/framework_basics/character_of_a_quantity.md b/docs/users_guide/framework_basics/character_of_a_quantity.md
index 2ce5a166..a47eb760 100644
--- a/docs/users_guide/framework_basics/character_of_a_quantity.md
+++ b/docs/users_guide/framework_basics/character_of_a_quantity.md
@@ -97,22 +97,22 @@ enumeration can be appended to the `quantity_spec` describing such a quantity ty
 === "C++23"
 
     ```cpp
-    inline constexpr struct position_vector final : quantity_spec<length, quantity_character::vector> {} position_vector;
     inline constexpr struct displacement final : quantity_spec<length, quantity_character::vector> {} displacement;
+    inline constexpr struct position_vector final : quantity_spec<displacement> {} position_vector;
     ```
 
 === "C++20"
 
     ```cpp
-    inline constexpr struct position_vector final : quantity_spec<position_vector, length, quantity_character::vector> {} position_vector;
     inline constexpr struct displacement final : quantity_spec<displacement, length, quantity_character::vector> {} displacement;
+    inline constexpr struct position_vector final : quantity_spec<position_vector, displacement> {} position_vector;
     ```
 
 === "Portable"
 
     ```cpp
-    QUANTITY_SPEC(position_vector, length, quantity_character::vector);
     QUANTITY_SPEC(displacement, length, quantity_character::vector);
+    QUANTITY_SPEC(position_vector, displacement);
     ```
 
 With the above, all the quantities derived from `position_vector` or `displacement` will have a correct
diff --git a/docs/users_guide/framework_basics/systems_of_quantities.md b/docs/users_guide/framework_basics/systems_of_quantities.md
index 3c24801a..f5df4d82 100644
--- a/docs/users_guide/framework_basics/systems_of_quantities.md
+++ b/docs/users_guide/framework_basics/systems_of_quantities.md
@@ -109,8 +109,8 @@ flowchart TD
     path_length --- distance["<b>distance</b>"]
     distance --- radial_distance["<b>radial_distance</b>"]
     length --- wavelength["<b>wavelength</b>"]
-    length --- position_vector["<b>position_vector</b><br>{vector}"]
     length --- displacement["<b>displacement</b><br>{vector}"]
+    displacement --- position_vector["<b>position_vector</b>"]
     radius --- radius_of_curvature["<b>radius_of_curvature</b>"]
 ```
 
@@ -164,8 +164,8 @@ For example, here is how the above quantity kind tree can be modeled in the libr
     inline constexpr struct distance final : quantity_spec<path_length> {} distance;
     inline constexpr struct radial_distance final : quantity_spec<distance> {} radial_distance;
     inline constexpr struct wavelength final : quantity_spec<length> {} wavelength;
-    inline constexpr struct position_vector final : quantity_spec<length, quantity_character::vector> {} position_vector;
     inline constexpr struct displacement final : quantity_spec<length, quantity_character::vector> {} displacement;
+    inline constexpr struct position_vector final : quantity_spec<displacement> {} position_vector;
     ```
 
 === "C++20"
@@ -186,8 +186,8 @@ For example, here is how the above quantity kind tree can be modeled in the libr
     inline constexpr struct distance final : quantity_spec<distance, path_length> {} distance;
     inline constexpr struct radial_distance final : quantity_spec<radial_distance, distance> {} radial_distance;
     inline constexpr struct wavelength final : quantity_spec<wavelength, length> {} wavelength;
-    inline constexpr struct position_vector final : quantity_spec<position_vector, length, quantity_character::vector> {} position_vector;
     inline constexpr struct displacement final : quantity_spec<displacement, length, quantity_character::vector> {} displacement;
+    inline constexpr struct position_vector final : quantity_spec<position_vector, displacement> {} position_vector;
     ```
 
 === "Portable"
@@ -208,8 +208,8 @@ For example, here is how the above quantity kind tree can be modeled in the libr
     QUANTITY_SPEC(distance, path_length);
     QUANTITY_SPEC(radial_distance, distance);
     QUANTITY_SPEC(wavelength, length);
-    QUANTITY_SPEC(position_vector, length, quantity_character::vector);
     QUANTITY_SPEC(displacement, length, quantity_character::vector);
+    QUANTITY_SPEC(position_vector, displacement);
     ```
 
 !!! note
diff --git a/src/systems/include/mp-units/systems/isq/space_and_time.h b/src/systems/include/mp-units/systems/isq/space_and_time.h
index a123f6dd..3061eaa3 100644
--- a/src/systems/include/mp-units/systems/isq/space_and_time.h
+++ b/src/systems/include/mp-units/systems/isq/space_and_time.h
@@ -42,8 +42,8 @@ QUANTITY_SPEC(thickness, width);
 QUANTITY_SPEC(diameter, width);
 QUANTITY_SPEC(distance, path_length);
 QUANTITY_SPEC(radial_distance, distance);
-QUANTITY_SPEC(position_vector, length, quantity_character::vector);
 QUANTITY_SPEC(displacement, length, quantity_character::vector);
+QUANTITY_SPEC(position_vector, displacement);
 QUANTITY_SPEC(radius_of_curvature, radius);
 QUANTITY_SPEC(curvature, inverse(radius_of_curvature));
 QUANTITY_SPEC(volume, pow<3>(length));