## Other Layers {toc} ### DG.LayerGroup Used to group several layers and handle them as one. If you add it to the map, any layers added or removed from the group will be added/removed on the map as well. Extends DG.Layer. DG.layerGroup([marker1, marker2]) .addLayer(polyline) .addTo(map); #### Creation

Factory	Description
`DG.layerGroup( <Layer[]> layers )`	Create a layer group, optionally given an initial set of layers.

#### Options Options inherited from Layer #### Events Events inherited from Layer #### Methods

Method	Returns	Description
`toGeoJSON()`	`Object`	Returns a `GeoJSON` representation of the layer group (as a GeoJSON `GeometryCollection`).
`addLayer( <Layer> layer )`	`this`	Adds the given layer to the group.
`removeLayer( <Layer> layer )`	`this`	Removes the given layer from the group.
`removeLayer( <Number> id )`	`this`	Removes the layer with the given internal ID from the group.
`hasLayer( <Layer> layer )`	`Boolean`	Returns `true` if the given layer is currently added to the group.
`clearLayers()`	`this`	Removes all the layers from the group.
`invoke( <string> methodName, … )`	`this`	Calls `methodName` on every layer contained in this group, passing any additional parameters. Has no effect if the layers contained do not implement `methodName`.
`eachLayer( <Function> fn, <Object> context? )`	`this`	Iterates over the layers of the group, optionally specifying context of the iterator function. `group.eachLayer(function (layer) { layer.bindPopup('Hello'); });`
`getLayer( <Number> id )`	`Layer`	Returns the layer with the given internal ID.
`getLayers()`	`Layer[]`	Returns an array of all the layers added to the group.
`setZIndex( <Number> zIndex )`	`this`	Calls `setZIndex` on every layer contained in this group, passing the z-index.
`getLayerId( <Layer> layer )`	`Number`	Returns the internal ID for a layer

Methods inherited from Layer Methods inherited from Evented ### DG.FeatureGroup Extended DG.LayerGroup that also has mouse events (propagated from members of the group) and a shared bindPopup method. DG.featureGroup([marker1, marker2, polyline]) .bindPopup('Hello world!') .on('click', function() { alert('Clicked on a group!'); }) .addTo(map); #### Creation

Factory	Description
`DG.featureGroup( <Layer[]> layers )`	Create a feature group, optionally given an initial set of layers.

#### Options Options inherited from Layer #### Events Events inherited from Layer #### Methods

Method	Returns	Description
`setStyle( <Path options> style )`	`this`	Sets the given path options to each layer of the group that has a `setStyle` method.
`bringToFront()`	`this`	Brings the layer group to the top of all other layers
`bringToBack()`	`this`	Brings the layer group to the top of all other layers
`getBounds()`	`LatLngBounds`	Returns the LatLngBounds of the Feature Group (created from bounds and coordinates of its children).

Methods inherited from LayerGroup Methods inherited from Layer Methods inherited from Evented ### DG.GeoJSON Represents a GeoJSON object or an array of GeoJSON objects. Allows you to parse GeoJSON data and display it on the map. Extends DG.FeatureGroup. DG.geoJson(data, { style: function (feature) { return {color: feature.properties.color}; } }).bindPopup(function (layer) { return layer.feature.properties.description; }).addTo(map); #### Creation

Factory	Description
`DG.geoJSON( <Object> geojson?, <GeoJSON options> options? )`	Creates a GeoJSON layer. Optionally accepts an object in GeoJSON format to display on the map (you can alternatively add it later with `addData` method) and an `options` object.

#### Options

Option	Type	Default	Description
`pointToLayer`	`Function`	`*`	A `Function` defining how GeoJSON points spawn maps API layers. It is internally called when data is added, passing the GeoJSON point feature and its `LatLng`. The default is to spawn a default `Marker`: `function(geoJsonPoint, latlng) { return DG.marker(latlng); }`
`style`	`Function`	`*`	A `Function` defining the `Path options` for styling GeoJSON lines and polygons, called internally when data is added. The default value is to not override any defaults: `function (geoJsonFeature) { return {} }`
`onEachFeature`	`Function`	`*`	A `Function` that will be called once for each created `Layer`, after it has been created and styled. Useful for attaching events and popups to features. The default is to do nothing with the newly created layers: `function (layer) {}`
`filter`	`Function`	`*`	A `Function` that will be used to decide whether to show a feature or not. The default is to show all features: `function (geoJsonFeature) { return true; }`
`coordsToLatLng`	`Function`	`*`	A `Function` that will be used for converting GeoJSON coordinates to `LatLng`s. The default is the `coordsToLatLng` static method.

Options inherited from Layer #### Events Events inherited from Layer #### Methods Methods inherited from FeatureGroup Methods inherited from LayerGroup Methods inherited from Layer Methods inherited from Evented #### Functions There are several static functions which can be called without instantiating DG.GeoJSON:

Function	Returns	Description
`geometryToLayer( <Object> featureData, <GeoJSON options> options? )`	`Layer`	Creates a `Layer` from a given GeoJSON feature. Can use a custom `pointToLayer` and/or `coordsToLatLng` functions if provided as options.
`coordsToLatLng( <Array> coords )`	`LatLng`	Creates a `LatLng` object from an array of 2 numbers (longitude, latitude) or 3 numbers (longitude, latitude, altitude) used in GeoJSON for points.
`coordsToLatLngs( <Array> coords, <Number> levelsDeep?, <Function> coordsToLatLng? )`	`Array`	Creates a multidimensional array of `LatLng`s from a GeoJSON coordinates array. `levelsDeep` specifies the nesting level (0 is for an array of points, 1 for an array of arrays of points, etc., 0 by default). Can use a custom `coordsToLatLng` function.
`latLngToCoords( <LatLng> latlng )`	`Array`	Reverse of `coordsToLatLng`
`latLngsToCoords( <Array> latlngs, <Number> levelsDeep?, <Boolean> closed? )`	`Array`	Reverse of `coordsToLatLngs` `closed` determines whether the first point should be appended to the end of the array to close the feature, only used when `levelsDeep` is 0. False by default.
`asFeature( <Object> geojson )`	`Object`	Normalize GeoJSON geometries/features into GeoJSON features.

### DG.GridLayer Generic class for handling a tiled grid of HTML elements. This is the base class for all tile layers and replaces TileLayer.Canvas. GridLayer can be extended to create a tiled grid of HTML Elements like <canvas>, <img> or <div>. GridLayer will handle creating and animating these DOM elements for you. #### Synchronous usage To create a custom layer, extend GridLayer and impliment the createTile() method, which will be passed a Point object with the x, y, and z (zoom level) coordinates to draw your tile. var CanvasLayer = DG.GridLayer.extend({ createTile: function(coords){ // create a

Option	Type	Default	Description
`tileSize`	`Number\|Point`	`256`	Width and height of tiles in the grid. Use a number if width and height are equal, or `DG.point(width, height)` otherwise.
`opacity`	`Number`	`1.0`	Opacity of the tiles. Can be used in the `createTile()` function.
`updateWhenIdle`	`Boolean`	`depends`	If `false`, new tiles are loaded during panning, otherwise only after it (for better performance). `true` by default on mobile browsers, otherwise `false`.
`updateInterval`	`Number`	`200`	Tiles will not update more than once every `updateInterval` milliseconds.
`attribution`	`String`	`null`	String to be shown in the attribution control, describes the layer data, e.g. "© 2GIS".
`zIndex`	`Number`	`1`	The explicit zIndex of the tile layer.
`bounds`	`LatLngBounds`	`undefined`	If set, tiles will only be loaded inside inside the set `LatLngBounds`.
`minZoom`	`Number`	`0`	The minimum zoom level that tiles will be loaded at. By default the entire map.
`maxZoom`	`Number`	`undefined`	The maximum zoom level that tiles will be loaded at.
`noWrap`	`Boolean`	`false`	Whether the layer is wrapped around the antimeridian. If `true`, the GridLayer will only be displayed once at low zoom levels.
`pane`	`String`	`'tilePane'`	`Map pane` where the grid layer will be added.

Event	Data	Description
`loading`	`Event`	Fired when the grid layer starts loading tiles
`tileunload`	`TileEvent`	Fired when a tile is removed (e.g. when a tile goes off the screen).
`tileloadstart`	`TileEvent`	Fired when a tile is requested and starts loading.
`tileerror`	`TileEvent`	Fired when there is an error loading a tile.
`tileload`	`TileEvent`	Fired when a tile loads.
`load`	`TileEvent`	Fired when the grid layer loaded all visible tiles.

Method	Returns	Description
`bringToFront()`	`this`	Brings the tile layer to the top of all tile layers.
`bringToBack()`	`this`	Brings the tile layer to the bottom of all tile layers.
`getAttribution()`	`String`	Used by the `attribution control`, returns the attribution option.
`getContainer()`	`String`	Returns the HTML element that contains the tiles for this layer.
`setOpacity( <Number> opacity )`	`this`	Changes the opacity of the grid layer.
`setZIndex( <Number> zIndex )`	`this`	Changes the zIndex of the grid layer.
`isLoading()`	`Boolean`	Returns `true` if any tile in the grid layer has not finished loading.
`redraw()`	`this`	Causes the layer to clear all the tiles and request them again.
`getTileSize()`	`Point`	Normalizes the tileSize option into a point. Used by the `createTile()` method.