update temporal literals

closes #483 closes #546
opengeospatial · Jul 19, 2021 · 0b7e5fd · 0b7e5fd
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diff --git a/extensions/cql/standard/annex_bibliography.adoc b/extensions/cql/standard/annex_bibliography.adoc
@@ -9,3 +9,5 @@
 * [[ogc-link-relations]] Open Geospatial Consortium (OGC). **OGC Link Relation Type Register** [online, viewed 2021-06-10], Available at http://www.opengis.net/def/rel
 * [[OpenAPI]] OpenAPI Initiative (OAI). **OpenAPI Specification 3.0** [online]. 2020 [viewed 2020-03-16]. The latest patch version at the time of publication of this standard was 3.0.3, available at http://spec.openapis.org/oas/v3.0.3
 * [[rfc3986]] Internet Engineering Task Force (IETF). RFC 3986: **Uniform Resource Identifier (URI): Generic Syntax** [online]. Edited by T. Berners-Lee, R. Fielding, L. Masinter. [viewed 2020-03-16]. Available at http://tools.ietf.org/rfc/rfc3986.txt
+* [[iso8601-1]] ISO 8601-1:2019, **Date and time — Representations for information interchange — Part 1: Basic rules**
+* [[iso8601-2]] ISO 8601-2:2019, **Date and time — Representations for information interchange — Part 2: Extensions**
diff --git a/extensions/cql/standard/clause_3_references.adoc b/extensions/cql/standard/clause_3_references.adoc
@@ -13,9 +13,5 @@ The following normative documents contain provisions that, through reference in
 
 * [[rfc3339]] Internet Engineering Task Force (IETF). RFC 3339: **Date and Time on the Internet: Timestamps** [online]. Edited by G. Klyne, C. Newman. 2002 [viewed 2020-03-16]. Available at http://tools.ietf.org/rfc/rfc3339.txt
 
-* [[iso8601-1]] ISO 8601-1:2019, **Date and time — Representations for information interchange — Part 1: Basic rules**
-
-* [[iso8601-2]] ISO 8601-2:2019, **Date and time — Representations for information interchange — Part 2: Extensions**
-
 * [[json-schema]] Internet Engineering Task Force (IETF). draft-handrews-json-schema-02: **JSON Schema: A Media Type for Describing JSON Documents** [online]. Edited by A. Wright, H. Andrews, B. Hutton, G. Dennis. 2019 [viewed 2020-11-22]. Available at https://tools.ietf.org/id/draft-handrews-json-schema-02.txt
 
diff --git a/extensions/cql/standard/clause_8_simple_cql.adoc b/extensions/cql/standard/clause_8_simple_cql.adoc
@@ -111,43 +111,43 @@ POLYGON((43.5845 -79.5442, 43.6079 -79.4893, 43.5677 -79.4632, 43.6129 -79.3925,
 ----
 * temporal geometry (instants, text)
 ----
-1969-07-20
-1969-07-20T20:17:40Z
+DATE("1969-07-20")
+TIMESTAMP("1969-07-20T20:17:40Z")
 ----
 * temporal geometry (instants, JSON)
 [source,JSON]
 ----
-"1969-07-20"
-"1969-07-20T20:17:40Z"
+{ "date": "1969-07-20" }
+{ "timestamp": "1969-07-20T20:17:40Z" }
 ----
 * temporal geometry (intervals, text)
 ----
-1969-07-16/1969-07-24
-1969-07-16T05:32:00Z/1969-07-24T16:50:35Z
-2019-09-09/..
+INTERVAL("1969-07-16", "1969-07-24")
+INTERVAL("1969-07-16T05:32:00Z", "1969-07-24T16:50:35Z")
+INTERVAL("2019-09-09", "..")
 ----
 * temporal geometry (intervals, JSON)
 [source,JSON]
 ----
-[ "1969-07-16", "1969-07-24" ]
-[ "1969-07-16T05:32:00Z", "1969-07-24T16:50:35Z" ]
-[ "2019-09-09", ".." ]
+{ "interval": [ "1969-07-16", "1969-07-24" ] }
+{ "interval": [ "1969-07-16T05:32:00Z", "1969-07-24T16:50:35Z" ] }
+{ "interval": [ "2019-09-09", ".." ] }
 ----
 ====
 
 For spatial and temporal geometries existing representations are used:
 
 * Spatial geometry:
-  * Text: an OGC Well-Known Text (WKT) literal
-  * JSON: a GeoJSON geometry object
+** Text: an OGC Well-Known Text (WKT) literal
+** JSON: a GeoJSON geometry object
 * Temporal instant:
-  * Text: an RFC 3339 literal
-  * JSON: a string of a RFC 3339 literal
+** Text: a `DATE` or `TIMESTAMP` function with a RFC 3339 literal string
+** JSON: an object with a `date` or `timestamp` member with a RFC 3339 literal string value
 * Temporal interval:
-  * Text: an ISO 8601-2 interval literal
-  * JSON: an array from an ISO 8601-2 interval literal that is split at the solidus
+** Text: an `INTERVAL` function with two temporal instants as parameters
+** JSON: an object with an `interval` member with an array of RFC 3339 literal string values (or ".." for an open end)
 
-NOTE: The current BNF rule for temporal literals supports timestamps in any time zone. Should this be restricted to UTC ("Z"), at least in Simple CQL? See https://github.com/opengeospatial/ogcapi-features/issues/483[issue 483].
+All temporal literals are in UTC ("Z").
 
 [[simple-cql_property]]
 === Property references

diff --git a/extensions/cql/standard/clause_9_enhanced.adoc b/extensions/cql/standard/clause_9_enhanced.adoc
@@ -271,15 +271,15 @@ include::requirements/temporal-operators/REQ_temporal-operators.adoc[]
 .Examples of temporal predicate using T_INTERSECTS
 ====
 ----
-event_date T_INTERSECTS 1969-07-16T05:32:00Z/1969-07-24T16:50:35Z
+T_INTERSECTS(event_date, INTERVAL("1969-07-16T05:32:00Z", "1969-07-24T16:50:35Z"))
 ----
 
 [source,JSON]
 ----
 {
    "t_intersects": [
       { "property": "event_date" },
-      [ "1969-07-16T05:32:00Z", "1969-07-24T16:50:35Z" ]
+      { "interval": [ "1969-07-16T05:32:00Z", "1969-07-24T16:50:35Z" ] }
    ]
 }
 ----
@@ -289,14 +289,14 @@ event_date T_INTERSECTS 1969-07-16T05:32:00Z/1969-07-24T16:50:35Z
 .Examples of temporal relationships using temporal literals.
 ====
 ----
-1969-07-20T20:17:40Z T_DURING 1969-07-16T13:32:00Z/1969-07-24T16:50:35Z
+T_DURING(DATE("1969-07-20T20:17:40Z"), INTERVAL("1969-07-16T13:32:00Z", "1969-07-24T16:50:35Z"))
 ----
 
 [source,JSON]
 ----
 {
-   "t_during": ["1969-07-20T20:17:40Z",["1969-07-16T13:32:00Z",
-                                        "1969-07-24T16:50:35Z"]]
+   "t_during": [ { "timestamp": "1969-07-20T20:17:40Z" },
+                 { "interval": ["1969-07-16T13:32:00Z", "1969-07-24T16:50:35Z"] } ]
 }
 ----
 ====
@@ -305,14 +305,14 @@ event_date T_INTERSECTS 1969-07-16T05:32:00Z/1969-07-24T16:50:35Z
 .Examples of temporal relationships using a property and a temporal literal.
 ====
 ----
-touchdown T_DURING 1969-07-16T13:32:00Z/1969-07-24T16:50:35Z
+T_DURING(touchdown, INTERVAL("1969-07-16T13:32:00Z", "1969-07-24T16:50:35Z"))
 ----
 
 [source,JSON]
 ----
 {
-   "t_during": [{"property": "touchdown"},["1969-07-16T13:32:00Z",
-                                           "1969-07-24T16:50:35Z"]]
+   "t_during": [ {"property": "touchdown"},
+                 {"interval": [ "1969-07-16T13:32:00Z", "1969-07-24T16:50:35Z"] } ]
 }
 ----
 ====

diff --git a/extensions/cql/standard/requirements/requirements_class_simple-cql.adoc b/extensions/cql/standard/requirements/requirements_class_simple-cql.adoc
@@ -7,7 +7,5 @@
 |Dependency |<<ogc06-103r4,OGC Simple feature access - Part 1: Common architecture, Architecture>>
 |Dependency |<<owl-time,W3C/OGC Time Ontology in OWL>>
 |Dependency |<<rfc3339,RFC 3339 (Date and Time on the Internet: Timestamps)>>
-|Dependency |<<iso8601-1,ISO 8601-1, Time interval>>
-|Dependency |<<iso8601-2,ISO 8601-2, Extended time interval representations>>
 |Dependency |<<json-schema,JSON Schema: A Media Type for Describing JSON Documents>>
 |===
diff --git a/extensions/cql/standard/schema/cql.bnf b/extensions/cql/standard/schema/cql.bnf
@@ -505,12 +505,6 @@ minElev = signedNumericLiteral;
 
 maxElev = signedNumericLiteral;
 
-#=============================================================================#
-# Definition of TEMPORAL literals
-#
-# NOTE: Is the fact the time zones are supported too complicated for a
-#       simple CQL? Perhaps the "core" of CQL should just support UTC.
-#=============================================================================#
 temporalLiteral = instantLiteral | intervalLiteral;
 
 instantLiteral = dateInstant | timestampInstant;
@@ -545,9 +539,7 @@ dateMonth  = digit digit;
 
 dateDay    = digit digit;
 
-utcTime  = timeHour ":" timeMinute ":" timeSecond [timeZoneOffset];
-
-timeZoneOffset = "Z" | sign timeHour [[colon] timeMinute];
+utcTime  = timeHour ":" timeMinute ":" timeSecond "Z";
 
 timeHour   = digit digit;