Draft for vector cubes

Author: m-mohr

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- A new Vector Cube Dimension
+
 ## [v2.0.0] - 2021-07-26
 
 ### Added

README.md

@@ -46,7 +46,7 @@ A spatial dimension in one of the horizontal (x or y) directions.
 | type             | string         | **REQUIRED.** Type of the dimension, always `spatial`.       |
 | axis             | string         | **REQUIRED.** Axis of the spatial dimension (`x`, `y`).      |
 | description      | string         | Detailed multi-line description to explain the dimension. [CommonMark 0.29](http://commonmark.org/) syntax MAY be used for rich text representation. |
-| extent           | \[number]      | **REQUIRED.** Extent (lower and upper bounds) of the dimension as two-dimensional array. Open intervals with `null` are not allowed. |
+| extent           | \[number]      | **REQUIRED.** Extent (lower and upper bounds) of the dimension as two-element array. Open intervals with `null` are not allowed. |
 | values           | \[number]      | Optionally, a set of all potential values.                   |
 | step             | number\|null   | The space between the values. Use `null` for irregularly spaced steps. |
 | reference_system | string\|number\|object | The spatial reference system for the data, specified as [numerical EPSG code](http://www.epsg-registry.org/), [WKT2 (ISO 19162) string](http://docs.opengeospatial.org/is/18-010r7/18-010r7.html) or [PROJJSON object](https://proj.org/specifications/projjson.html). Defaults to EPSG code 4326. |
@@ -60,7 +60,7 @@ A spatial dimension in vertical (z) direction.
 | type             | string           | **REQUIRED.** Type of the dimension, always `spatial`.       |
 | axis             | string           | **REQUIRED.** Axis of the spatial dimension, always `z`.     |
 | description      | string           | Detailed multi-line description to explain the dimension. [CommonMark 0.29](http://commonmark.org/) syntax MAY be used for rich text representation. |
-| extent           | \[number\|null\]   | If the dimension consists of [ordinal](https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale) values, the extent (lower and upper bounds) of the values as two-dimensional array. Use `null` for open intervals. |
+| extent           | \[number\|null\]   | If the dimension consists of [ordinal](https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale) values, the extent (lower and upper bounds) of the values as two-element array. Use `null` for open intervals. |
 | values           | \[number\|string\] | A set of all potential values, especially useful for [nominal](https://en.wikipedia.org/wiki/Level_of_measurement#Nominal_level) values. |
 | step             | number\|null     | If the dimension consists of [interval](https://en.wikipedia.org/wiki/Level_of_measurement#Interval_scale) values, the space between the values. Use `null` for irregularly spaced steps. |
 | unit             | string           | The unit of measurement for the data, preferably compliant to [UDUNITS-2](https://ncics.org/portfolio/other-resources/udunits2/) units (singular). |
@@ -77,10 +77,22 @@ A temporal dimension based on the ISO 8601 standard. The temporal reference syst
 | ---------- | --------------- | ------------------------------------------------------------ |
 | type       | string          | **REQUIRED.** Type of the dimension, always `temporal`.      |
 | description | string         | Detailed multi-line description to explain the dimension. [CommonMark 0.29](http://commonmark.org/) syntax MAY be used for rich text representation. |
-| extent     | \[string\|null] | **REQUIRED.** Extent (lower and upper bounds) of the dimension as two-dimensional array. The dates and/or times must be strings compliant to [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601). `null` is allowed for open date ranges. |
+| extent     | \[string\|null] | **REQUIRED.** Extent (lower and upper bounds) of the dimension as two-element array. The dates and/or times must be strings compliant to [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601). `null` is allowed for open date ranges. |
 | values     | \[string]       | If the dimension consists of set of specific values they can be listed here. The dates and/or times must be strings compliant to [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601). |
 | step       | string\|null    | The space between the temporal instances as [ISO 8601 duration](https://en.wikipedia.org/wiki/ISO_8601#Durations), e.g. `P1D`. Use `null` for irregularly spaced steps. |
 
+### Vector Dimension Object
+
+A vector dimension that defines the spatial extent based on a geometry.
+
+| Field Name       | Type           | Description                                                  |
+| ---------------- | -------------- | ------------------------------------------------------------ |
+| type             | string         | **REQUIRED.** Type of the dimension, always `vector`.        |
+| description      | string         | Detailed multi-line description to explain the dimension. [CommonMark 0.29](http://commonmark.org/) syntax MAY be used for rich text representation. |
+| bbox             | \[number]      | **REQUIRED.** A single bounding box of the geometries as defined for [STAC Collections](https://github.com/radiantearth/stac-spec/blob/master/collection-spec/collection-spec.md#spatial-extent-object), but not nested. |
+| values           | \[[GeoJSON Geometry Object](https://tools.ietf.org/html/rfc7946#section-3.1)] | Optionally, a set of all geometries. |
+| reference_system | string\|number\|object | The spatial reference system for the data, specified as [numerical EPSG code](http://www.epsg-registry.org/), [WKT2 (ISO 19162) string](http://docs.opengeospatial.org/is/18-010r7/18-010r7.html) or [PROJJSON object](https://proj.org/specifications/projjson.html). Defaults to EPSG code 4326. |
+
 ### Additional Dimension Object
 
 An additional dimension that is not `spatial`, but may be `temporal` if the data is not compliant with ISO 8601 (see below).
@@ -89,7 +101,7 @@ An additional dimension that is not `spatial`, but may be `temporal` if the data
 | ---------------- | ----------------- | ------------------------------------------------------------ |
 | type             | string            | **REQUIRED.** Custom type of the dimension, never `spatial`. |
 | description      | string            | Detailed multi-line description to explain the dimension. [CommonMark 0.29](http://commonmark.org/) syntax MAY be used for rich text representation. |
-| extent           | \[number\|null]   | If the dimension consists of [ordinal](https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale) values, the extent (lower and upper bounds) of the values as two-dimensional array. Use `null` for open intervals. |
+| extent           | \[number\|null]   | If the dimension consists of [ordinal](https://en.wikipedia.org/wiki/Level_of_measurement#Ordinal_scale) values, the extent (lower and upper bounds) of the values as two-element array. Use `null` for open intervals. |
 | values           | \[number\|string] | A set of all potential values, especially useful for [nominal](https://en.wikipedia.org/wiki/Level_of_measurement#Nominal_level) values. |
 | step             | number\|null      | If the dimension consists of [interval](https://en.wikipedia.org/wiki/Level_of_measurement#Interval_scale) values, the space between the values. Use `null` for irregularly spaced steps. |
 | unit             | string            | The unit of measurement for the data, preferably compliant to [UDUNITS-2](https://ncics.org/portfolio/other-resources/udunits2/) units (singular). |

json-schema/schema.json

@@ -193,6 +193,9 @@
           {
             "$ref": "#/definitions/vertical_spatial_dimension"
           },
+          {
+            "$ref": "#/definitions/vector_dimension"
+          },
           {
             "$ref": "#/definitions/temporal_dimension"
           }
@@ -347,6 +350,50 @@
         }
       }
     },
+    "vector_dimension": {
+      "title": "Vector Dimension Object",
+      "type": "object",
+      "required": [
+        "type",
+        "extent"
+      ],
+      "properties": {
+        "type": {
+          "type": "string",
+          "const": "vector"
+        },
+        "description": {
+          "$ref": "#/definitions/description"
+        },
+        "bbox": {
+          "title": "Spatial extent",
+          "type": "array",
+          "oneOf": [
+            {
+              "minItems":4,
+              "maxItems":4
+            },
+            {
+              "minItems":6,
+              "maxItems":6
+            }
+          ],
+          "items": {
+            "type": "number"
+          }
+        },
+        "values": {
+          "type": "array",
+          "minItems": 1,
+          "items": {
+            "$ref": "https://geojson.org/schema/Geometry.json"
+          }
+        },
+        "reference_system": {
+          "$ref": "#/definitions/reference_system_spatial"
+        }
+      }
+    },
     "temporal_dimension": {
       "title": "Temporal Dimension Object",
       "type": "object",