spec: add UUID to multiscales metadata

examples/multiscales_strict/multiscales_example.json

@@ -7,6 +7,7 @@
       "multiscales": [
         {
           "name": "example",
+          "uuid": "5a1443a1-5af7-48ec-9115-7272af5c41f2",
           "coordinateSystems": [
               {
                 "name": "intrinsic",

examples/multiscales_strict/multiscales_example_relative.json

@@ -1,8 +1,8 @@
 {
   "multiscales": [
     {
-      "version": "0.6.dev3",
       "name": "example",
+      "uuid": "4b954a85-63f2-48e0-8fb8-f2d436109869",
       "coordinateSystems" : [
         {
           "name" : "world",

examples/multiscales_strict/multiscales_transformations.json

@@ -60,6 +60,7 @@
             }
           ],
           "name": "image_with_coordinateTransformations",
+          "uuid": "e3a3177d-2097-4c23-bc1b-9d0e5b934fc3",
           "type": "foo",
           "metadata": {
             "key": "value"

index.md

@@ -1305,6 +1305,15 @@ which gives the type of downscaling method used to generate the multiscale image
 It SHOULD contain the field `metadata`,
 which contains a object with additional information about the downscaling method.
 
+Each `multiscales` object SHOULD contain the field `uuid`,
+which is a  [RFC 4122](https://www.ietf.org/rfc/rfc4122.txt) compliant string representation of a universally unique identifier,
+(e.g., `"urn":"uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6"`)
+and SHOULD use a compliant generator to minimize potential conflicts.
+
+The uuid field is used to uniquely assign an identity to objects in the dataset.
+Users MAY choose to store identical objects, i.e. with the same uuid,
+in multiple filesets with the intent that changes to either may eventually be applied to all copies.
+
 
 :::{dropdown} Example
 

schemas/image.schema

@@ -38,6 +38,10 @@
           "name": {
             "type": "string"
           },
+          "uuid": {
+            "type": "string",
+            "format": "uuid"
+          },
           "datasets": {
             "type": "array",
             "minItems": 1,

tests/attributes/spec/invalid/image/multiscales_bad_uuid.json

@@ -0,0 +1,73 @@
+{
+	"ome": {
+		"version": "0.6.dev3",
+		"multiscales": [
+			{
+				"name": "multiscales",
+				"uuid": 123,
+				"coordinateSystems": [
+					{
+						"name": "physical",
+						"axes": [
+							{
+								"type": "space",
+								"name": "z",
+								"unit": "micrometer",
+								"discrete": false
+							},
+							{
+								"type": "space",
+								"name": "y",
+								"unit": "micrometer",
+								"discrete": false
+							},
+							{
+								"type": "space",
+								"name": "x",
+								"unit": "micrometer",
+								"discrete": false
+							}
+						]
+					}
+				],
+				"datasets": [
+					{
+						"path": "array",
+						"coordinateTransformations": [
+							{
+								"type": "sequence",
+								"output": "physical",
+								"input": "array",
+								"transformations": [
+									{
+										"type": "scale",
+										"scale": [
+											4,
+											3,
+											2
+										]
+									},
+									{
+										"type": "translation",
+										"translation": [
+											30,
+											20,
+											10
+										]
+									}
+								],
+								"name": "transform-name"
+							}
+						]
+					}
+				]
+			}
+		]
+  },
+	"_conformance": {
+		"schema": {
+					"id": "schemas/image.schema"
+		},
+		"valid": false
+	}
+}

tests/attributes/spec/valid/image/multiscales_transform_sequence.json

@@ -4,6 +4,7 @@
 		"multiscales": [
 			{
 				"name": "multiscales",
+				"uuid": "urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6",
 				"coordinateSystems": [
 					{
 						"name": "physical",