Feature/image in alerts

gtfs-realtime/proto/gtfs-realtime.proto

@@ -634,6 +634,12 @@ message Alert {
 
   optional SeverityLevel severity_level = 14 [default = UNKNOWN_SEVERITY];
 
+  // List of URL linking to an image to be displayed along the alert text. Used to explain visually the alert effect of a detour, station closure, etc. The image should enhance the understanding of the alert and must not be the only location of essential information.
+  // The following types of images are discouraged : image containing mainly text, marketing or branded images that add no additional information. 
+  // The image linked need to be PNG or JPG of less than 500kB. 
+  // NOTE: This field is still experimental, and subject to change. It may be formally adopted in the future.
+  repeated TranslatedString image_url = 15; 
+
   // The extensions namespace allows 3rd-party developers to extend the
   // GTFS Realtime Specification in order to add and evaluate new features
   // and modifications to the spec.

gtfs-realtime/spec/en/reference.md

@@ -38,38 +38,61 @@ Fields labeled as **experimental** are subject to change and not yet formally ad
 
 ## Element Index
 
-*   [FeedMessage](#message-feedmessage)
-    *   [FeedHeader](#message-feedheader)
-        *   [Incrementality](#enum-incrementality)
-    *   [FeedEntity](#message-feedentity)
-        *   [TripUpdate](#message-tripupdate)
-            *   [TripDescriptor](#message-tripdescriptor)
-                *   [ScheduleRelationship](#enum-schedulerelationship-1)
-            *   [VehicleDescriptor](#message-vehicledescriptor)
-            *   [StopTimeUpdate](#message-stoptimeupdate)
-                *   [StopTimeEvent](#message-stoptimeevent)
-                *   [ScheduleRelationship](#enum-schedulerelationship)
-                *   [StopTimeProperties](#message-stoptimeproperties)
-            *   [TripProperties](#message-tripproperties)
-        *   [VehiclePosition](#message-vehicleposition)
-            *   [TripDescriptor](#message-tripdescriptor)
-                *   [ScheduleRelationship](#enum-schedulerelationship-1)
-            *   [VehicleDescriptor](#message-vehicledescriptor)
-            *   [Position](#message-position)
-            *   [VehicleStopStatus](#enum-vehiclestopstatus)
-            *   [CongestionLevel](#enum-congestionlevel)
-            *   [OccupancyStatus](#enum-occupancystatus)
-            *   [CarriageDetails](#message-carriagedetails)
-        *   [Alert](#message-alert)
-            *   [TimeRange](#message-timerange)
-            *   [EntitySelector](#message-entityselector)
-                *   [TripDescriptor](#message-tripdescriptor)
-                    *   [ScheduleRelationship](#enum-schedulerelationship-1)
-            *   [Cause](#enum-cause)
-            *   [Effect](#enum-effect)
-            *   [TranslatedString](#message-translatedstring)
-                *   [Translation](#message-translation)
-            *   [SeverityLevel](#enum-severitylevel)
+- [Elements](#elements)
+  - [_message_ FeedMessage](#message-feedmessage)
+      - [Fields](#fields)
+  - [_message_ FeedHeader](#message-feedheader)
+      - [Fields](#fields-1)
+  - [_enum_ Incrementality](#enum-incrementality)
+      - [Values](#values)
+  - [_message_ FeedEntity](#message-feedentity)
+      - [Fields](#fields-2)
+  - [_message_ TripUpdate](#message-tripupdate)
+      - [Fields](#fields-3)
+  - [_message_ StopTimeEvent](#message-stoptimeevent)
+      - [Fields](#fields-4)
+  - [_message_ StopTimeUpdate](#message-stoptimeupdate)
+      - [Fields](#fields-5)
+  - [_enum_ ScheduleRelationship](#enum-schedulerelationship)
+      - [Values](#values-1)
+  - [_message_ StopTimeProperties](#message-stoptimeproperties)
+      - [Fields](#fields-6)
+  - [_message_ TripProperties](#message-tripproperties)
+      - [Fields](#fields-7)
+  - [_message_ VehiclePosition](#message-vehicleposition)
+      - [Fields](#fields-8)
+  - [_enum_ VehicleStopStatus](#enum-vehiclestopstatus)
+      - [Values](#values-2)
+  - [_enum_ CongestionLevel](#enum-congestionlevel)
+      - [Values](#values-3)
+  - [_enum OccupancyStatus_](#enum-occupancystatus)
+      - [_Values_](#values-4)
+  - [_message_ CarriageDetails](#message-carriagedetails)
+      - [Fields](#fields-9)
+  - [_message_ Alert](#message-alert)
+      - [Fields](#fields-10)
+  - [_enum_ Cause](#enum-cause)
+      - [Values](#values-5)
+  - [_enum_ Effect](#enum-effect)
+      - [Values](#values-6)
+  - [_enum_ SeverityLevel](#enum-severitylevel)
+      - [Values](#values-7)
+  - [_message_ TimeRange](#message-timerange)
+      - [Fields](#fields-11)
+  - [_message_ Position](#message-position)
+      - [Fields](#fields-12)
+  - [_message_ TripDescriptor](#message-tripdescriptor)
+      - [Fields](#fields-13)
+  - [_enum_ ScheduleRelationship](#enum-schedulerelationship-1)
+      - [Values](#values-8)
+  - [_message_ VehicleDescriptor](#message-vehicledescriptor)
+      - [Fields](#fields-14)
+  - [_message_ EntitySelector](#message-entityselector)
+      - [Fields](#fields-15)
+  - [_message_ TranslatedString](#message-translatedstring)
+      - [Fields](#fields-16)
+  - [_message_ Translation](#message-translation)
+      - [Fields](#fields-17)
 
 # Elements
 
@@ -333,6 +356,7 @@ An alert, indicating some sort of incident in the public transit network.
 | **tts_header_text** | [TranslatedString](#message-translatedstring) | Optional | One | Text containing the alert's header to be used for text-to-speech implementations. This field is the text-to-speech version of header_text. It should contain the same information as header_text but formatted such that it can read as text-to-speech (for example, abbreviations removed, numbers spelled out, etc.) |
 | **tts_description_text** | [TranslatedString](#message-translatedstring) | Optional | One | Text containing a description for the alert to be used for text-to-speech implementations. This field is the text-to-speech version of description_text. It should contain the same information as description_text but formatted such that it can be read as text-to-speech (for example, abbreviations removed, numbers spelled out, etc.) |
 | **severity_level** | [SeverityLevel](#enum-severitylevel) | Optional | One | Severity of the alert. |
+| **image_url** | [TranslatedString](#message-translatedstring) | Optional | Many | URL linking to an image to be displayed along the alert text. Used to explain visually the alert effect of a detour, station closure, etc. The image should enhance the understanding of the alert and must not be the only location of essential information.  The image linked need to be PNG or JPG of less than 500kB. <br><br>**Caution:** this field is still **experimental**, and subject to change. It may be formally adopted in the future. |
 
 ## _enum_ Cause