torque/doc/API.md

Torque API

L.TorqueLayer(options)

One of two core classes for the Torque library - it is used to create an animated torque layer with custom settings.

Usage example

  // initialize a torque layer that uses the CartoDB account details and SQL API to pull in data
  var torqueLayer = new L.TorqueLayer({
    user       : 'viz2',
    table      : 'ow',
    cartocss:  CARTOCSS
  });

Options

Provider options

Option	type	Default	Description
provider	string	sql_api	Where is the data coming from

CartoDB data options (SQL API provider)

Option	type	Default	Description
user	string	null	CartoDB account name. Found as, accountname.cartodb.com
table	string	null	CartoDB table name where data is found
sql	string	null	SQL query to be performed to fetch the data. You must
use this param or table, not at the same time

Time methods

Method	options	returns	Description
setStep(step)	time numeric	this	sets the animation to the step indicated by step, must be between 0 and steps
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
getTime()		current animation time (Date)	gets the real animation time

Style methods

Method	options	returns	Description
setCartoCSS(cartocss)	cartocss string	this	style the map rendering using client-side cartocss

The full CartoCSS spec is not supported by Torque but instead only a limited subset with some additions related to torque rendering. To see the full list of supported parameters, read the Torque CartoCSS documentation here. value and zoom variables can be used. value is the value of aggregation (see countby constructor option). zoom is the current zoom being rendered

TorqueLayer currently expects marker styling

CartoCSS Example

This should be string encoded in Javascript

#layer {,
  marker-fill: #662506;
  marker-width: 20;
  [value > 1] { marker-fill: #FEE391; }
  [value > 2] { marker-fill: #FEC44F; }
  [value > 3] { marker-fill: #FE9929; }
  [value > 4] { marker-fill: #EC7014; }
  [value > 5] { marker-fill: #CC4C02; }
  [value > 6] { marker-fill: #993404; }
  [value > 7] { marker-fill: #662506; }
  [frame-offset = 1] {  marker-width: 20; marker-fill-opacity: 0.05;}', // renders the previos frame
  [frame-offset = 2] {  marker-fill: red; marker-width: 30; marker-fill-opacity: 0.02;}', // renders two frames ago from the current being rendered
}

Interaction methods (only available for Leaflet)

Method	options	returns	Description
getValueForPos(x, y[, step])		an object like { bbox:[], value: VALUE } if there is value for the pos, null otherwise	allows to get the value for the coordinate (in map reference system) for a concrete step. If step is not specified the animation one is used. This method is expensive in terms of CPU so be careful. It returns the value from the raster data not the rendered data
getActivePointsBBox(step)		list of bbox	returns the list of bounding boxes active for step

Google Maps Layers

GMapsTorqueLayer(options)

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

Options

options

Option	type	Default	Description
map	google.maps.Map		google.maps.Map instance

see L.TorqueLayer for the rest of the options.