Class: Reader

H .data .geojson.Reader

new H.data.geojson.Reader (opt_url, opt_options)

This class represents a GeoJSON reader responsible for fetching and interpreting GeoJSON data. It creates an instance of H.map.Object that can be displayed on the map (for more details see GeoJSON documentation).

Auxiliary data that accompanies geometries (the contents of the field properties) is bound to the map object and can be fetched with the method getData() on that object. See H.map.Object#getData.

Note that you can load a GeoJSON file even from a different domain, if that domain supports Cross-Origin Resource Sharing.

Name	Type	Description
`opt_url`	string	optional The optional URL of the data file.
`opt_options`	H.data.geojson.Reader.Options	optional An object providing additional reader configuration parameters.

Example

var reader = new H.data.geojson.Reader('/path/to/geojson/file.json');
reader.parse();
// Assumption: map already exists
map.addLayer(reader.getLayer());

Extends

H.data.AbstractReader

Methods

addEventListener (type, handler, opt_capture, opt_scope) inherited

This method adds a listener for a specific event.

Note that to prevent potential memory leaks, you must either call removeEventListener or dispose on the given object when you no longer need it.

Name	Type	Description
`type`	string	The name of the event
`handler`	function	An event handler function
`opt_capture`	boolean	optional `true` indicates that the method should listen in the capture phase (bubble otherwise)
`opt_scope`	Object	optional An object defining the scope for the handler function

addOnDisposeCallback (callback, opt_scope) inherited

This method adds a callback which is triggered when the EventTarget object is being disposed.

Name	Type	Description
`callback`	function	The callback function.
`opt_scope`	Object	optional An optional scope for the callback function

dispatchEvent (evt) inherited

This method dispatches an event on the EventTarget object.

Name	Type	Description
`evt`	H.util.Event \| string	An object representing the event or a string with the event name

dispose () inherited

This method removes listeners from the given object. Classes that extend EventTarget may need to override this method in order to remove references to DOM Elements and additional listeners.

getLayer ()H.map.layer.ObjectLayer inherited

This method retrieves an object layer (H.map.layer.ObjectLayer) that contains parsed data and can be added directly to the map. The method gets a new instance of ObjectLayer with every invocation. If the data has not been parsed, the method returns an ObjectLayer that contains partial information, and the reader adds any new parsed objects to the provider associated with the layer later on.

Returns:

Type	Description
H.map.layer.ObjectLayer

getParsedObjects ()Array.<!H.map.Object> inherited

This method retrieves a collection of objects representing parsed data converted to data objects. Note that the method returns only currently parsed objects if parsing is ongoing.

Returns:

Type	Description
Array.<!H.map.Object>	An array of objects representing parsed data

getState ()H.data.AbstractReader.State inherited

This method retrieves the processing state of the Reader. For possible states see H.data.AbstractReader.State.

Returns:

Type	Description
H.data.AbstractReader.State	A value indicating the state of the `Reader`

getUrl ()string | undefined inherited

This method retrieves the URL of the current file, which is either a file being fetched/parsed or a file that has been already parsed.

Returns:

Type	Description
string \| undefined	url A string containing the URL or `undefined`

parse () inherited

This method launches parsing of the data file at the current URL (see H.data.AbstractReader#setUrl or H.data.AbstractReader). The method uses XHR as a transport, therefore the same origin policy applies, or the server should respond with the appropriate CORS headers.

parseData (data)

This method launches the parsing process on the provided data.

Name	Type	Description
`data`	string \| Object	A string or object containing the data to parse

removeEventListener (type, handler, opt_capture, opt_scope) inherited

This method removes a previously added listener from the EventTarget instance.

Name	Type	Description
`type`	string	The name of the event
`handler`	function	A previously added event handler
`opt_capture`	boolean	optional `true` indicates that the method should listen in the capture phase (bubble otherwise)
`opt_scope`	Object	optional An object defining the scope for the handler function

setUrl (url)H.data.AbstractReader inherited

This method sets the URL for the Reader. It resets the current state of the Reader to its initial values (clears data about last parsed objects, etc.), and throws InvalidState exception if the state of the Reader is not READY or ERROR.

Name	Type	Description
`url`	string	The new URL

Returns:

Type	Description
H.data.AbstractReader	An object reflecting the `Reader` after modification

Type Definitions

H.data.geojson.Reader.Options Object

This type encapsulates configuration (initialization) properties for a H.data.geojson.Reader.

Properties:

Name	Type	Argument	Description
`style`	function	<optional>	A function to be invoked during the parsing process, after object creation, and is used to set the style of the object.
`disableLegacyMode`	boolean	<optional>	A flag indicating whether GeoJSON geometry types MultiPoint, MultiLineString, MultiPolygon should be represented respectively by `H.geo.MultiPoint`, `H.geo.MultiLineString` and `H.geo.MultiPolygon`. To maximise compatibility when fetching data from remote services and enabling features like polygon interiors it is recommended to set this flag to `true`. For backward compatibility with older releases of the API the default value of the flag is `false`.

Events

statechange inherited

Event fired when the reader state changes, see H.data.AbstractReader#getState.

Type:

H.data.AbstractReader.Event