Merge pull request #190 from usdot-jpo-ode/update-date-clarification

Clarify RoadEventFeedInfo update_date definition

create-feed/schemas/wzdx_v3.1_feed.json

@@ -59,7 +59,7 @@
           "minimum": 1
         },
         "update_date": {
-          "description": "The UTC date and time when the data feed was last updated",
+          "description": "The UTC date and time when the GeoJSON file (representing the instance of the feed) was generated",
           "type": "string",
           "format": "date-time"
         },

spec-content/objects/RoadEventFeedInfo.md

@@ -8,7 +8,7 @@ Name | Type | Description | Conformance | Notes
 `version` | String | The WZDx specification version used to create the data feed in `major.minor` format. Note this mandates that all data in a WZDx feed complies to a single version of WZDx. | Required | Examples: `1.1`, `2.0`
 `license` | String; [uri](https://tools.ietf.org/html/draft-handrews-json-schema-validation-01#section-7.3.5); "https://creativecommons.org/publicdomain/zero/1.0/" | The URL of the license that applies to the data in the WZDx feed. This *must* be the string "https://creativecommons.org/publicdomain/zero/1.0/". | Optional | Data in all public WZDx feeds must be licensed under the [Creative Commons - Public Domian License (CC0)](https://creativecommons.org/share-your-work/public-domain/cc0/) which permits consumers to freely publish the enclosed information. This property is currently optional but *will be required in a future release*. 
 `data_sources` | Array; \[[RoadEventDataSource](/spec-content/objects/RoadEventDataSource.md)\] | A list of specific data sources for the road event data in the feed. | Required | Length of array must be at least one.
-`update_date` |	String; [date-time](https://tools.ietf.org/html/draft-handrews-json-schema-validation-01#section-7.3.1) | The UTC date and time when the data feed was last updated. | Required | All date-time formats shall follow [RFC 3339 Section 5.6](https://tools.ietf.org/html/rfc3339#section-5.6). Example: `2016-11-03T19:37:00Z`
+`update_date` |	String; [date-time](https://tools.ietf.org/html/draft-handrews-json-schema-validation-01#section-7.3.1) | The UTC date and time when the GeoJSON file (representing the instance of the feed) was generated. | Required | The recency of the value of this property depends on if the feed producer is generating a new feed GeoJSON file for each request or generating the file in advance and making it available for download (WZDx does not mandate a particular distribution method). Note all date-time formats shall follow [RFC 3339 Section 5.6](https://tools.ietf.org/html/rfc3339#section-5.6). Example: `2016-11-03T19:37:00Z`
 `update_frequency` | Integer | The frequency in seconds at which the data feed is updated. | Optional | Example: `60`
 `contact_name` | String | The name of the individual or group responsible for the data feed. | Optional | Example: `Jo Help`
 `contact_email` | String; [email](https://tools.ietf.org/html/draft-handrews-json-schema-validation-01#section-7.3.2) | The email address of the individual or group responsible for the data feed. | Optional | Example: `abc@testcity1.gov`