ome · thewtex · Sep 3, 2026 · Aug 31, 2026
diff --git a/rfc/4/index.md b/rfc/4/index.md
@@ -579,3 +579,4 @@ End-user applications SHOULD display the encoded information with, for example,
 | 2026-06-04 | Clarify that an absent `orientation` and an explicit `null` `orientation` are equivalent and leave the orientation undefined. | [https://github.com/fideus-labs/ngff-zarr/pull/523](https://github.com/fideus-labs/ngff-zarr/pull/523) |
 | 2026-06-12 | Clarify that `orientation` describes a single, primary orientation; note that secondary orientations are not supported and could be expressed via a future generic vector data structure, and record the primary-vs-secondary alternative considered. | [https://github.com/ome/ngff/pull/528](https://github.com/ome/ngff/pull/528) |
 | 2026-08-27 | Take the `type` constant and the `AnatomicalOrientationValues` range back into the generated artifacts, which had stopped enforcing the vocabulary this document defines. | [https://github.com/ome/ngff/pull/595](https://github.com/ome/ngff/pull/595) |
+| 2026-09-01 | Give the `orientation` slot its range directly, so the generated schema stops emitting a stray `type: string` beside the `AnatomicalOrientation` reference and the TypeScript interface types the attribute. | [https://github.com/ome/ngff/pull/599](https://github.com/ome/ngff/pull/599) |
diff --git a/rfc/4/markdown/AnatomicalOrientation.md b/rfc/4/markdown/AnatomicalOrientation.md
@@ -9,14 +9,15 @@ orphan: true
 URI: [ngff:AnatomicalOrientation](https://w3id.org/ome/ngff/AnatomicalOrientation)
 
 
-[![img](https://yuml.me/diagram/nofunky;dir:TB/class/[Orientation],[Orientation]^-[AnatomicalOrientation&#124;type:string;value:AnatomicalOrientationValues])](https://yuml.me/diagram/nofunky;dir:TB/class/[Orientation],[Orientation]^-[AnatomicalOrientation&#124;type:string;value:AnatomicalOrientationValues])
+[![img](https://yuml.me/diagram/nofunky;dir:TB/class/[Orientation],[SpaceAxis]++-%20orientation%200..1>[AnatomicalOrientation&#124;type:string;value:AnatomicalOrientationValues],[Orientation]^-[AnatomicalOrientation],[SpaceAxis])](https://yuml.me/diagram/nofunky;dir:TB/class/[Orientation],[SpaceAxis]++-%20orientation%200..1>[AnatomicalOrientation&#124;type:string;value:AnatomicalOrientationValues],[Orientation]^-[AnatomicalOrientation],[SpaceAxis])
 
 ## Parents
 
  *  is_a: [Orientation](Orientation.md)
 
 ## Referenced by Class
 
+ *  **None** *[➞orientation](spaceAxis__orientation.md)*  <sub>0..1</sub>  **[AnatomicalOrientation](AnatomicalOrientation.md)**
 
 ## Attributes
 

diff --git a/rfc/4/markdown/SpaceAxis.md b/rfc/4/markdown/SpaceAxis.md
@@ -9,7 +9,7 @@ orphan: true
 URI: [ngff:SpaceAxis](https://w3id.org/ome/ngff/SpaceAxis)
 
 
-[![img](https://yuml.me/diagram/nofunky;dir:TB/class/[Axis]^-[SpaceAxis&#124;unit:SpaceUnit;orientation:string%20%3F;name:SpaceAxesNames;type:string],[Axis])](https://yuml.me/diagram/nofunky;dir:TB/class/[Axis]^-[SpaceAxis&#124;unit:SpaceUnit;orientation:string%20%3F;name:SpaceAxesNames;type:string],[Axis])
+[![img](https://yuml.me/diagram/nofunky;dir:TB/class/[AnatomicalOrientation]<orientation%200..1-++[SpaceAxis&#124;unit:SpaceUnit;name:SpaceAxesNames;type:string],[Axis]^-[SpaceAxis],[Axis],[AnatomicalOrientation])](https://yuml.me/diagram/nofunky;dir:TB/class/[AnatomicalOrientation]<orientation%200..1-++[SpaceAxis&#124;unit:SpaceUnit;name:SpaceAxesNames;type:string],[Axis]^-[SpaceAxis],[Axis],[AnatomicalOrientation])
 
 ## Parents
 
@@ -30,7 +30,7 @@ URI: [ngff:SpaceAxis](https://w3id.org/ome/ngff/SpaceAxis)
  * [➞orientation](spaceAxis__orientation.md)  <sub>0..1</sub>
      * Description: The direction of an axis of type space. This attribute is OPTIONAL. An axis with no orientation and an axis whose orientation is null are equivalent: in both cases the orientation of that axis is undefined, and neither implies a default value. Writers SHOULD omit the attribute rather than serialize a null value.
 
-     * Range: [String](types/String.md)
+     * Range: [AnatomicalOrientation](AnatomicalOrientation.md)
  * [SpaceAxis➞name](SpaceAxis_name.md)  <sub>1..1</sub>
      * Range: [SpaceAxesNames](SpaceAxesNames.md)
  * [SpaceAxis➞type](SpaceAxis_type.md)  <sub>1..1</sub>

diff --git a/rfc/4/markdown/spaceAxis__orientation.md b/rfc/4/markdown/spaceAxis__orientation.md
@@ -11,7 +11,7 @@ URI: [ngff:spaceAxis__orientation](https://w3id.org/ome/ngff/spaceAxis__orientat
 
 ## Domain and Range
 
-None &#8594;  <sub>0..1</sub> [String](types/String.md)
+None &#8594;  <sub>0..1</sub> [AnatomicalOrientation](AnatomicalOrientation.md)
 
 ## Parents
 

diff --git a/rfc/4/orientation.py b/rfc/4/orientation.py
@@ -354,9 +354,7 @@ class SpaceAxis(Axis):
     unit: SpaceUnit = Field(default=..., description="""Physical unit for spatial measurement along the axis, selected from a standardized list of distance units (e.g., micrometer, nanometer).
 """, json_schema_extra = { "linkml_meta": {'alias': 'unit', 'domain_of': ['SpaceAxis', 'TimeAxis']} })
     orientation: Optional[AnatomicalOrientation] = Field(default=None, description="""The direction of an axis of type space. This attribute is OPTIONAL. An axis with no orientation and an axis whose orientation is null are equivalent: in both cases the orientation of that axis is undefined, and neither implies a default value. Writers SHOULD omit the attribute rather than serialize a null value.
-""", json_schema_extra = { "linkml_meta": {'alias': 'orientation',
-         'any_of': [{'range': 'AnatomicalOrientation'}],
-         'domain_of': ['SpaceAxis']} })
+""", json_schema_extra = { "linkml_meta": {'alias': 'orientation', 'domain_of': ['SpaceAxis']} })
     name: SpaceAxesNames = Field(default=..., json_schema_extra = { "linkml_meta": {'alias': 'name', 'domain_of': ['Axis']} })
     type: Literal["space"] = Field(default="space", json_schema_extra = { "linkml_meta": {'alias': 'type',
          'domain_of': ['Axis', 'Orientation'],

diff --git a/rfc/4/orientation.schema.json b/rfc/4/orientation.schema.json
@@ -147,8 +147,7 @@
                             "type": "null"
                         }
                     ],
-                    "description": "The direction of an axis of type space. This attribute is OPTIONAL. An axis with no orientation and an axis whose orientation is null are equivalent: in both cases the orientation of that axis is undefined, and neither implies a default value. Writers SHOULD omit the attribute rather than serialize a null value.\n",
-                    "type": "string"
+                    "description": "The direction of an axis of type space. This attribute is OPTIONAL. An axis with no orientation and an axis whose orientation is null are equivalent: in both cases the orientation of that axis is undefined, and neither implies a default value. Writers SHOULD omit the attribute rather than serialize a null value.\n"
                 },
                 "type": {
                     "const": "space",

diff --git a/rfc/4/orientation.ts b/rfc/4/orientation.ts
@@ -175,7 +175,7 @@ export interface SpaceAxis extends Axis {
     unit: string,
     /** The direction of an axis of type space. This attribute is OPTIONAL. An axis with no orientation and an axis whose orientation is null are equivalent: in both cases the orientation of that axis is undefined, and neither implies a default value. Writers SHOULD omit the attribute rather than serialize a null value.
  */
-    orientation?: string,
+    orientation?: AnatomicalOrientation,
 }
 
 

diff --git a/rfc/4/orientation.yml b/rfc/4/orientation.yml
@@ -91,8 +91,7 @@ classes:
           The direction of an axis of type space. This attribute is OPTIONAL. An axis with no orientation and an axis
           whose orientation is null are equivalent: in both cases the orientation of that axis is undefined, and
           neither implies a default value. Writers SHOULD omit the attribute rather than serialize a null value.
-        any_of:
-          - range: AnatomicalOrientation
+        range: AnatomicalOrientation
         required: false
     defining_slots:
       - name