Road link attributes in HERE Route Matching API v8 response

Road link attributes, like speed limits or slope from HERE Map Attributes API v8 layers can be retrieved directly in the HERE Route Matching API v8 response. For certain use cases, this approach is a better alternative to calling HERE Map Attributes API v8 tile or spatial search. Use the &attributes=... parameter to get selected attributes of each layer.

When to get road link attributes

Should you request for route link attributes directly in the HERE Route Matching API v8 call, or should you get them later from HERE Map Attributes API v8?

HERE Route Matching API v8	HERE Map Attributes API v8
- Getting attributes when calling HERE Route Matching API v8 is an easier operation on the client side.	- HERE Map Attributes API v8 tile data can be cached up to a month. This reduces costs, as less calls can be made for assets that don't change their area of operation.
- HERE Route Matching API v8 returns the attributes data only for the route links that are a part of the route, which reduces the amount of transferred data.	- HERE Map Attributes API v8 returns full tile content, which requires more data transfer.
- Requesting more attributes in a single call increases the cost of the HERE Route Matching API v8 call.

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Note
The more attributes you request in a HERE Route Matching API v8 call, the higher the cost.

Layers compatible with route matching

HERE Route Matching API v8 allows you to request for map attributes from layers that contain information for specific Functional Classes of roads.

The names of such layers end with FCn, where n is the number of the Functional Class for which the layer contains data.

This is the list of layers that can be used in HERE Route Matching API v8 calls:

Layer name	Description
`ADAS_ATTRIB_FCn`	More detailed representation of road geometry for ADAS.
`APPLICABLE_SPEED_LIMIT`	Applicable speed limit for the given vehicle specification for the given time along the given route-matched path.
`BASIC_HEIGHT_FCn`	Link height values on the reference and non-reference node of a link.
`DISTANCE_MARKERS_FCn`	Sequentially numbered markers placed along roads at regular intervals that serve as reference location signs.
`EVCHARGING_POI`	Charging stations for electric vehicles.
`FUELSTATION_POI`	Gas stations.
`LANE_FCn`	Link lane attributes.
`LINK_ATTRIBUTE_FCn`	Road link attributes.
`LINK_ATTRIBUTE2_FCn`	Road link attributes.
`LINK_TMC_FCn`	For each link, defines towards which Traffic Message Channel (TMC) point location it leads.
`LOADING_ZONE_POI`	Loading dock and loading zone point of interest (POI).
`POINT_ADDRESS`	Address point information.
`POI_BIG`	POIs ordered by national and visual significance.
`POI_BIGGER`	POIs ordered by national and visual significance.
`POI_SMALL`	POIs ordered by national and visual significance.
`POI_SMALLER`	POIs ordered by national and visual significance.
`PUBLIC_TRANSPORT_POI`	Public transport points of interest.
`ROAD_ADMIN_FCn`	Permanent IDs of administrative hierarchy for road links.
`ROAD_GEOM_FCn`	Ungeneralized road, ferry, and rail ferry geometry (polylines).
`ROAD_NAME_FCn`	Road names.
`ROAD_ROUGHNESS_FCn`	Multiple representations of the measured roughness of a link.
`ROUNDABOUT_FCn`	Roundabouts.
`SPEED_LIMITS_FCn`	Posted and derived legal speed limits.
`SPEED_LIMITS_COND_FCn`	Conditional speed limits.
`SPEED_LIMITS_VAR_FCn`	Variable speed limits on links with their direction and sign location.
`TOLL_BOOTH_FCn`	Toll booths.
`TOLL_LINK_FCn`	Toll information on road links.
`TOPO_SEG_ID_FCn`	Topology segment IDs for the roads.
`TOPO_SEG_LINK_FCn`	Link IDs of a topology segment for the roads.
`TRAFFIC_PATTERN_FCn`	Link traffic patterns.
`TRUCK_PARKING_POI`	Truck parking POIs (US).
`TRUCK_PARKING_POI_STATUS`	Dynamic content of truck parking POIs (US).
`TRUCK_POI`	Truck points of interest (POI).
`TRAFFIC_SIGN_FCn`	Traffic signs.
`TRUCK_SPEED_LIMITS_FCn`	Speed limits for trucks, buses, or road trains.
`TRAFFIC_SPEED_RECORD_FCn`	Historic traffic flow data from the last seven days for the given time along the given route-matched path.
`TRUCK_RESTR_FCn`	Restrictions for trucks.
`TURN_RESTR_FCn`	Link-based routing restrictions.

Data in layers

Every layer consists of a single flat table with simple records in numbers or text strings, represented as attribute key-value pairs.

When requesting for road link attributes, you must specify the layer you want to get the data from as well as the column in the data table.

For example, this is the data from the SPEED_LIMITS_FC1 layer for a specific map tile:

| LINK_ID   | FROM_REF_SPEED_LIMIT | TO_REF_SPEED_LIMIT | SOURCE | UNIT |
| --------- | -------------------- | ------------------ | ------ | ---- |
| 566084098 | null                 | 80                 | 1      | K    |
| 566084207 | 100                  | 100                | 1      | K    |
| 566089718 | null                 | 100                | 1      | K    |
| 578304140 | null                 | 100                | 1      | K    |
| 578313250 | 100                  | null               | 1      | K    |

To get all data from this layer, use &attributes=SPEED_LIMITS_FC1(*) in the API call.
To get the data from the FROM_REF_SPEED_LIMIT and TO_REF_SPEED_LIMIT columns, use &attributes=SPEED_LIMITS_FC1(FROM_REF_SPEED_LIMIT,TO_REF_SPEED_LIMIT) in the API call.
To get all data from all SPEED_LIMITS layers, use &attributes=SPEED_LIMITS_FCn(*) in the API call.

To get a list of all available attribute layers and the data they contain, use the /v8/maps/layers/list.html resource. Access the following URL replacing the placeholder with your API key:

https://smap.hereapi.com/v8/maps/layers/list.html?apiKey=YOUR_API_KEY

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Note
The order of the columns in layers can change and new columns can be added. Make sure that your applications take this into account.

Data volume optimization

To reduce the volume of data transferred, many columns in layers are denormalized or encoded.

To get details for specific layers, access the following URL replacing the placeholders with a layer name and your API key.

https://smap.hereapi.com/v8/maps/layers/doc.html?layer=LAYER_NAME&apiKey=YOUR_API_KEY