4 min read
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on Sep 2, 2015
How to stream location data to build realtime location tracking maps using JavaScript, EON realtime dashboard framework, and the Mapbox API.

Realtime Location Tracking on a Map using JavaScript

In this tutorial, we’ll show you how to get started with realtime location tracking on a live-updating map using the EON framework and the Mapbox API, all in JavaScript. In a nutshell, our application will stream data from a connected user in realtime with their location, and publish that data to a map. As the user moves, their marker on the map reflects their change of location.

Check out our live demos below:

For an overview of how EON works, including a getting started guide for the overall framework, check out our Getting Started with Realtime JavaScript Dashboards.

Click here for the full EON GitHub repository.

Now, let’s get started!

Quickstart

Init

Parameter Value Default
id The ID of the element where the map will be rendered. undefined
mb_token Mapbox API Token. undefined
mb_id Mapbox Map ID. undefined
transform Method for changing the payload format of your stream. function(m){}
history Use PubNub history call to retrieve last message. This will display points at their last known location. Requires PubNub Storage & Playback to be enabled. false
pubnub An instance of the PUBNUB javascript global. This is required when using your own keys. See the subscribe_key example. false
connect A function to call when PubNub makes a connection. See PubNub subscribe. function(){}
marker A custom Mapbox marker object. Use this to change the marker icon, tooltip, etc. L.maker
rotate Add bearing to markers in options.angle. This won’t have any effect unless you’re using a rotated marker type. false

Simple Example

Call eon.map({}). Check out the table of options above for more information.

Realtime Location Tracking on a Map using JavaScript

Lat/Long Values

eon.map expects an array of objects to be published on the same channel it’s subscribed to. More on publishing in the next section.

For example, below you can find a list of all the Torchy’s Tacos in Austin, TX.

Publishing Messages

The function below is called connect and fires when the pubnub_mapbox library is ready.

This function uses the included PubNub library to pubnub.publish() packets to the pubnub.subscribe() call waiting inside the Mapbox framework.

Notice how the subscribe_key and channel matches.

You may want to publish data from the back-end instead, and in that case, check out our docs for our back-end SDKs (we have over 70 total!).

Following a Point

You can tell the map to follow a point to its new location whenever data is received by supplying a message callback.

Marker Customization

You can supply a custom Mapbox marker object with custom tooltips by extending the L.marker object provided by the Mapbox API. Learn more about custom Mapbox API markers here.

Configure Using Your Own PubNub API Keys

Using your own API Key with EON Maps

To get your unique publish/subscribe keys, you’ll first need to sign up for a PubNub account. Once you sign up, you can get your unique PubNub keys in the PubNub Developer Dashboard. Our free Sandbox tier should give you all the bandwidth you need to build and test your app with the PubNub API.

You can set the pubnub init parameter when using EON for realtime maps. This allows you to configure PubNub client connections with extra security options such a auth_key and your cipher_key.

You should also set secure: true and ssl: true as well.

Customizing with Mapbox

The MapBox map object is returned by eon.mapbox and can be customized using the Mapbox API. See the Mapbox examples page.

You can also customize your map using the Mapbox map editor. You can change the map background style, add static markers, etc. Visit Mapbox for your own API key.

Distributed Systems

The EON library compiles all messages at designated intervals. This means you can publish from multiple sources into one map.

For example, you can map the individual locations of three phones by supplying the same channel to your PubNub publish requests. The flight example works like this; not every flight is updated on every subscribe call.

That’s all for this realtime location tracking maps getting started. Stay tuned for future tutorials on building realtime dashboards with EON!

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