docs: describe GeoJSON fields in directions response

CHANGELOG.md

@@ -30,6 +30,7 @@ Releasing is documented in RELEASE.md
 ### Added
 - accept [`sac_scale=strolling`](https://wiki.openstreetmap.org/wiki/Key:sac_scale) ([#2149](https://github.com/GIScience/openrouteservice/pull/2149))
 - show export endpoint in status ([#2105](https://github.com/GIScience/openrouteservice/issue/2105))
+- Documentation on the fields of Json and Geojson responses of the directions endpoint ([#2084](https://github.com/GIScience/openrouteservice/issue/2084)
 
 ### Changed
 

docs/api-reference/endpoints/directions/requests-and-return-types.md

@@ -20,14 +20,38 @@ Additionally, there is one simple GET request that does not allow advanced reque
 
 The **JSON** return type is best suited for further processing.
 
-### GPX
-
-The **GPX** return type is an XML dialect from openrouteservice based on the [GPS Exchange Format](https://www.topografix.com/gpx.asp) with an own [XML Schema](https://raw.githubusercontent.com/GIScience/openrouteservice-schema/main/gpx/v2/ors-gpx.xsd).
-It is a very old standard for lightweight interchange of GPS data and thus being used by hundreds of software programs and Web services.
-
 ### GeoJSON
 
 **GeoJSON** is a format for encoding a variety of geographic data structures, see [geojson.org](https://datatracker.ietf.org/doc/html/rfc7946).
 It is widely used and can therefore be easily processed or displayed in many applications, e.g. in [QGIS](https://qgis.org/) or on [geojson.io](http://geojson.io/)
 
 More information about the result types can be found in the [API Playground](https://openrouteservice.org/dev/#/api-docs/directions_service).
+
+### Shared Structure (JSON and GeoJSON)
+
+Both the **JSON** and **GeoJSON** outputs contain the same routing information, organized in slightly different formats.
+
+| Field            | Description                                                                                                                                                                                    |
+| ---------------- |------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| **`summary`**    | Total `distance` (m) and `duration` (s) for the route.                                                                                                                                         |
+| **`segments`**   | List of route parts between waypoints, each with `distance`, `duration`, and `steps`.                                                                                                          |
+| **`steps`**      | Turn-by-turn navigation instructions with `instruction`, `name`, `distance` (m), `duration` (s), and `way_points`.                                                                             |
+| **`way_points`** | Indices marking the start and end positions of each segment along the geometry.                                                                                                                |
+| **`bbox`**       | Bounding box `[minLon, minLat, maxLon, maxLat]` of the route.                                                                                                                                  |
+| **`geometry`**   | The path of the route. In JSON it is [encoded](https://developers.google.com/maps/documentation/utilities/polylinealgorithm), while in GeoJSON it is a `LineString` with explicit coordinates. |
+| **`metadata`**   | Contains additional details about the request and routing engine, including `attribution`, `service`, `timestamp`, `query`, and `engine` info.                                                 |
+
+In the **GeoJSON** format, the route data is organized as a standard **FeatureCollection**:
+
+* **`type`**: `"FeatureCollection"`
+* **`features`**: array of route features
+
+    * each **feature** includes
+
+        * **`geometry`**: route path as a `LineString`
+        * **`properties`**: contains the same information as in the JSON format (`summary`, `segments`, `steps`, etc.)
+
+### GPX
+
+The **GPX** return type is an XML dialect from openrouteservice based on the [GPS Exchange Format](https://www.topografix.com/gpx.asp) with an own [XML Schema](https://raw.githubusercontent.com/GIScience/openrouteservice-schema/main/gpx/v2/ors-gpx.xsd).
+It is a very old standard for lightweight interchange of GPS data and thus being used by hundreds of software programs and Web services.