Metadata and APIs

The Metadata API, Query API, and Index API provide flexible ways of discovering metadata (partitions) optimized for specific use cases.

Metadata API and Query API

When working with versioned layers, the Metadata API supports consolidated views of partitions representing the latest logically consistent version of the catalog. It also notes the discovery of changes between multiple catalog versions to support incremental compilations of map content.

The Query API provides very similar functionality to the Metadata API, but is optimized for map-panning and interactive UI use cases that require queries on quadtree levels.

Note

For the Metadata and Query APIs, queries should not exceed 500 requests/sec per client appId.

Index API

The Index API supports RSQL queries to retrieve matching partitions from an index layer. You can significantly improve query time by optimizing your data model. HERE recommends that you evaluate your workload, for example, how the data will be queried, read/write ratio, and other similar factors before designing your data model. The Index API supports defining up to four custom indices that allow for very fine-grained data retrieval workflows.

The Index API, in combination with the Data Archiving Library (part of the HERE Data SDK for Java & Scala), provides a way to create an archive of messages ingested via a stream layer.

Note

The Index Layer Service can return HTTP 429/503 when service utilization is high. Throttling should last for only short period of time.

The client should retry the request using an exponential backoff algorithm while the service adapts to the high utilization.

When an extended period of throttling and retries occurs and the service still returns HTTP 429/503, please contact the HERE technical support.

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