Clarify how to distinguish a TemporalDimension with an AdditionalDime…

…nsion object where type = 'temporal' #5

CHANGELOG.md

@@ -19,6 +19,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Clarified that EPSG codes must be numbers, PROJJSON must be objects and WKT2 must be a string.
+- Clarified how to distinguish a Temporal Dimension from an Additional Dimension with type 'temporal'. [#5](https://github.com/stac-extensions/datacube/issues/5)
+
 
 ## [v1.0.0] - 2021-03-08
 

README.md

@@ -80,7 +80,7 @@ A temporal dimension based on the ISO 8601 standard. The temporal reference syst
 
 ### Additional Dimension Object
 
-An additional dimension that is not `spatial`, but may be `temporal` if the data is not compliant with ISO 8601.
+An additional dimension that is not `spatial`, but may be `temporal` if the data is not compliant with ISO 8601 (see below).
 
 | Field Name       | Type              | Description                                                  |
 | ---------------- | ----------------- | ------------------------------------------------------------ |
@@ -94,6 +94,8 @@ An additional dimension that is not `spatial`, but may be `temporal` if the data
 
 An Additional Dimension Object MUST specify an `extent` or a set of `values`. It MAY specify both.
 
+Note on "Additional Dimension" with type `temporal`: You can distinguish the "Temporal Dimension" from an "Additional Dimension" by checking whether the extent exists and contains strings. So if the `type` equals `temporal` and `extent` is an array of strings/null, then you have a "Temporal Dimension", otherwise you have an "Additional Dimension".
+
 ## Contributing
 
 All contributions are subject to the