adding JSON schema for pointcloud extension

CHANGELOG.md

@@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ## [Unreleased]
 
 ### Added
+- JSON-schema file in the Point Cloud extension.
 
 ### Changes
 

extensions/pointcloud/README.md

@@ -12,7 +12,7 @@ come from either active or passive sensors, and data is frequently acquired usin
 tools such as LiDAR or coincidence-matched imagery.
 
 - [Example](examples/example-autzen.json)
-- JSON Schema is missing. PRs are welcome.
+- [JSON Schema](json-schema/schema.json)
 
 ## Item Fields
 
@@ -34,21 +34,20 @@ the point cloud, their types, and their sizes (in full bytes).
 | ---------- | ------- | -------------------------- |
 | name       | string  | **REQUIRED.** The name of the dimension. |
 | size       | integer | **REQUIRED.** The size of the dimension in bytes. Whole bytes only are supported. |
-| type       | string  | **REQUIRED.** Dimension type. Valid values include `floating`, `unsigned`, and `signed` |
+| type       | string  | **REQUIRED.** Dimension type. Valid values are `floating`, `unsigned`, and `signed` |
 
 ### Stats Object
 
-A sequential array of items mapping to `pc:schemas` defines per-channel statistics. All fields
-are optional.
+A sequential array of items mapping to `pc:schemas` defines per-channel statistics. The channel name is required and at least one statistic.
 
 | Field Name | Type    | Description |
 | ---------- | ------- | ----------- |
+| name       | string  | **REQUIRED.** The name of the channel. |
+| position   | integer | Position of the channel in the schema. |
 | average    | number  | The average of the channel. |
 | count      | integer | The number of elements in the channel. |
 | maximum    | number  | The maximum value of the channel. |
 | minimum    | number  | The minimum value of the channel. |
-| name       | string  | The name of the channel. |
-| position   | integer | Position of the channel in the schema. |
 | stddev     | number  | The standard deviation of the channel. |
 | variance   | number  | The variance of the channel. |
 

extensions/pointcloud/json-schema/schema.json

@@ -0,0 +1,130 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://schemas.stacspec.org/dev/extensions/pointcloud/json-schema/schema.json#",
+  "title": "Point Cloud Extension",
+  "description": "STAC Point Cloud Extension to a STAC Item",
+  "allOf": [
+    {
+      "$ref": "../../../item-spec/json-schema/item.json"
+    },
+    {
+      "$ref": "#/definitions/pointcloud"
+    }
+  ],
+  "definitions": {
+    "pointcloud": {
+      "type": "object",
+      "required": [
+        "stac_extensions",
+        "properties"
+      ],
+      "properties": {
+        "stac_extensions": {
+          "type": "array",
+          "contains": {
+            "enum": [
+              "pointcloud",
+              "https://schemas.stacspec.org/dev/extensions/pointcloud/json-schema/schema.json"
+            ]
+          }
+        },
+        "properties": {
+          "type": "object",
+          "required": [
+            "pc:count",
+            "pc:type",
+            "pc:encoding",
+            "pc:schemas"
+          ],
+          "properties": {
+            "pc:count": {
+              "type": "integer",
+              "minimum": 0
+            },
+            "pc:type": {
+              "type": "string"
+            },
+            "pc:encoding": {
+              "type": "string"
+            },
+            "pc:schemas": {
+              "type": "array",
+              "minItems": 1,
+              "items": {
+                "$ref": "#/definitions/schema"
+              }
+            },
+            "pc:density": {
+              "type": "number",
+              "minimum": 0
+            },
+            "pc:statistics": {
+              "type": "array",
+              "minItems": 1,
+              "items": {
+                "$ref": "#/definitions/stats"
+              }
+            }
+          }
+        }
+      }
+    },
+    "schema": {
+      "type": "object",
+      "required": [
+        "name",
+        "size",
+        "type"
+      ],
+      "properties": {
+        "name": {
+          "type": "string"
+        },
+        "size": {
+          "type": "integer"
+        },
+        "type": {
+          "type": "string",
+          "enum": [
+            "floating",
+            "unsigned",
+            "signed"
+          ]
+        }
+      }
+    },
+    "stats": {
+      "type": "object",
+      "minProperties": 2,
+      "required": [
+        "name",
+      ],
+      "properties": {
+        "name": {
+          "type": "string"
+        },
+        "position": {
+          "type": "integer"
+        },
+        "average": {
+          "type": "number"
+        },
+        "count": {
+          "type": "integer"
+        },
+        "maximum": {
+          "type": "number"
+        },
+        "minimum": {
+          "type": "number"
+        },
+        "stddev": {
+          "type": "number"
+        },
+        "variance": {
+          "type": "number"
+        }
+      }
+    }
+  }
+}