Torque.js is an efficient and stylish rendering method to animate your data.

Introduction

Torque.js is an efficient and stylish rendering method to animate your data.

The contents described in this document are subject to CARTO’s Terms of Service

Versioning

Torque.js uses Semantic Versioning. View our Github repository to find tags for each release.

L.TorqueLayer

A layer to be added to a Leaflet map. It works as a regular tiled layer within the Leaflet tile pane, but instead of containing <img> elements, it’s composed of a single <canvas> where all markers are drawn.

Example:

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var torqueLayer = new L.TorqueLayer({
  user: 'viz2',
  table: 'ow',
  cartocss: '<cartocss here>'
});

map.addLayer(torqueLayer);

Options

Name Description
cartocss A string object, the CartoCSS style for the map. Default value is null
loop A boolean object that defines the animation loop. Default value is true. If false, the animation is paused when it reaches the last frame
resolution Spatial resolution in pixels. A resolution of 1 means no spatial aggregation of the data. Its value must be a power of 2
steps Number of steps that the animation is divided into
animationDuration Duration, in seconds, of the animation
zIndex Z-Index CSS property of the layer
attribution Attribution to be added in the bottom right of the map
maxZoom Maximum zoom for the layer.
tileSize Size, in pixels of the tiles

Using a CARTO table directly

Name Description
user A string object, your CARTO account name. Default value is null
table A string object, the CARTO table name where data is found (also known as a dataset.) Default value is null

Using a custom SQL query

Name | Description — | — query | A string object, the SQL query to be performed to fetch the data. Default value is null.

You must use this param or table, but not at the same time Tip: For a Torque category layer that is created dynamically with cartodb.createLayer, the SQL query must explicitly include how to build the torque_category column. You must include both the sql and table_name parameters. See this createLayer with torque category layer example.

Providing a TileJSON file

Name Description
tileJSON A URL pointing to a valid TileJSON file from which to get the Torque tile templates

Add Comment

Time Methods

Method Options Returns Description
setStep(step) time numeric this the value must be between 0 and the total number of steps in the animation
play()   this starts the animation
stop()   this stops the animation and set time to step 0
pause()   this stops the animation but keep the current time (play enables the animation again)
toggle()   this toggles (pause/play) the animation
getStep()   current animation step (integer) gets the current animation step. A step is considered an animation frame
getTime()   current animation time (Date) gets the real animation time
isRunning()   true/false describes whether the Torque layer is playing or is stopped

Note: Torque.js interprets the beginning and ending date/time from your “Time Column” as one block, then divides that up into Steps, depending on the number you set. It does not necessarily draw one frame for each row.

Layer Control Methods

Method Options Returns Description
hide() none this hides the Torque layer
show() none this shows the Torque layer

Style Methods

Method Options Returns Description
setCartoCSS(cartocss) cartocss string this style the map rendering using client-side CartoCSS (not available with Named maps)

Torque supports a limited subset of CartoCSS rules defined in the torque-reference. To see the full list of supported rules, read the Torque CartoCSS documentation. value and zoom variables can be used. value is the value of aggregation. zoom is the current zoom being rendered.

TorqueLayer currently expects marker styling.

Example:

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/* This is how a minimal example of a stylesheet for a Torque visualisation would look like. */

Map {
  -torque-time-attribute: "date";
  -torque-aggregation-function: "count(cartodb_id)";
  -torque-frame-count: 760;
  -torque-animation-duration: 15;
  -torque-resolution: 2;
}
#layer {
  marker-width: 3;
  marker-fill-opacity: 0.8;
  marker-fill: #FEE391; 
}
#layer[value = 4] { // Use of the value variable, generated by the function specified in -torque-aggregation-function
  marker-fill: #FABADA; 
}
#layer[zoom = 12] { // Use of the zoom variable
  marker-width: 10;
}

Data Methods

Method Options Returns Description
setSQL(sql statement) SQL string this Change the SQL on the data table (not available with named maps)
error(callback) callback function with a list of errors as argument this specifies a callback function to run if there are query errors

Example: ```js // SQL Example to limit the data used in the Torque map. torqueLayer.setSQL(“SELECT * FROM table LIMIT 100”);

Events

Events in Torque follow the format:

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torqueLayer.on('event-type', function([callback_obj]) {
  // do something
});
Events Callback Object Description
change:steps current step When a map changes steps, this event is triggered
change:time current time, step number When a map changes time, this event is triggered
play none Triggered when the Torque layer is played
pause none Triggered when the Torque layer is paused
stop none Triggered when the Torque layer is stopped
load none Triggered when the Torque layer is loaded

Example:

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// An event example to print the current step to the console log.

torqueLayer.on('change:steps', function(step) {
  // do something with step
  console.log('Current step is ' + step);
});

Google Maps Layers

GMapsTorqueLayer(options)

This class does exactly the same as L.TorqueLayer but using Google Maps instead. The main difference is that this class is not a layer but is an overlay, so in order to add it to the a map use, layer.setMap instead of overlayMapTypes. See the Overlay View reference in Google Maps API doc.

Options

Name Description
map A google.maps.Map instance