openlr_decoder

A general purpose OpenLR decoding solution for any suitable road network.

Introduction

OpenLR is a dynamic location reference standard to enable systems to exchange location information in a map-agnostic manner. For further info see OpenLR association. This module provides a simple and performant solution to decode an openLR reference.

Dependencies

This module requires a mongodb database instance or an Azure Cosmos instance with support for mongodb api enabled.

Support for more backends will be added in future releases.

Installation

Install the module with npm:

npm install openlr_decoder

Install the preferred backend driver (only mongodb currently supported):

npm install mongodb

Example Usage

Initialise a storage connection with the chosen storage backend, the database url, and database name.

Decode an OpenLR string providing the string and any options.

import {decodeOpenLR, initStorage, storageBackends, closeConnection} from "openlr_decoder";

async main(){

    // Backend storage connection options
    const options = {
        storageBackend: storageBackends.mongodb,
        url: "127.0.0.1:27017",
        dbName: "streetMap"
    }

    await initStorage(options);

    const result = await decodeOpenLr("C/+/+yY40CuxDAA6/WgrHw==", {targetBearing: 25, searchRadius: 100});

    await closeConnection();

}

Storage Schema

The module expects data in the below described schemas for the chosen storage medium.

• mongodb

Mongo Collection Design

The module expects the mongodb database to have a collection named "nodes" which contains only node documents. Each node should contain two arrays named startLinks and endLinks. The startLinks array contains links which start from this node and the endLinks array contains links which end at this node. A JSON schema file is provided here.

A ready to use nodes collection of OpenStreetMap data, for the UK county of Lincolnshire, is provided for download here. The corresponding links are also provided to allow the geometry of a full route to be identified here. All OpenStreetMap data is copyright OpenStreetMap contributors