168 lines
6.8 KiB
Markdown
168 lines
6.8 KiB
Markdown
# Torque API
|
|
|
|
### L.TorqueLayer(options)
|
|
|
|
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>`](https://developer.mozilla.org/en-US/docs/Web/API/Canvas_API) where all markers are drawn.
|
|
|
|
```javascript
|
|
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 CartoDB table directly
|
|
|
|
Name | Description
|
|
--- | ---
|
|
user | A string object, your CartoDB [account name](/cartodb-editor/your-account/#account). Default value is ```null```
|
|
table | A string object, the CartoDB 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```.<br/><br/>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](https://gist.github.com/danicarrion/dcaf6f00a71aa55134b4) example.
|
|
|
|
##### Providing a TileJSON file
|
|
|
|
Name | Description
|
|
--- | ---
|
|
tileJSON | A URL pointing to a valid [TileJSON](https://github.com/mapbox/tilejson-spec) file from which to get the Torque tile templates
|
|
|
|
#### 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](/cartodb-platform/cartocss/properties-for-torque/#torque-frame-count-number), 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](/cartodb-platform/maps-api/named-maps/))
|
|
|
|
Torque supports a limited subset of CartoCSS rules defined in the [torque-reference](https://github.com/cartodb/torque-reference). To see the full list of supported rules, read the [Torque CartoCSS documentation](/cartodb-platform/cartocss/properties-for-torque/). `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
|
|
|
|
This is how a minimal example of a stylesheet for a Torque visualisation would look like.
|
|
|
|
```css
|
|
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
|
|
|
|
SQL Example to limit the data used in the Torque map.
|
|
|
|
```js
|
|
torqueLayer.setSQL("SELECT * FROM table LIMIT 100");
|
|
```
|
|
|
|
### Events
|
|
|
|
_**Note:** You can only run events after the [required libraries](/cartodb-platform/torque/torquejs-getting-started/#advanced-torquejs-libraries) are loaded. Otherwise, the [interaction methods](/cartodb-platform/torque/torque-interaction-methods/) will not work._
|
|
|
|
Events in Torque follow the format:
|
|
|
|
```js
|
|
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
|
|
|
|
An event example to print the current step to the console log.
|
|
|
|
```js
|
|
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](https://developers.google.com/maps/documentation/javascript/reference#OverlayView) reference in Google Maps API doc.
|
|
|
|
#### Options
|
|
|
|
Name | Description
|
|
--- | ---
|
|
map | A google.maps.Map instance
|