OpenLayers. Layer. UTFGrid

This Layer reads from UTFGrid tiled data sources. Since UTFGrids are essentially JSON-based ASCII art with attached attributes, they are not visibly rendered. In order to use them in the map, you must add a OpenLayers.Control.UTFGrid control as well.

Example

var world_utfgrid = new OpenLayers.Layer.UTFGrid({
    url: "/tiles/world_utfgrid/${z}/${x}/${y}.json",
    utfgridResolution: 4,
    displayInLayerSwitcher: false
);
map.addLayer(world_utfgrid);

var control = new OpenLayers.Control.UTFGrid({
    layers: [world_utfgrid],
    handlerMode: 'move',
    callback: function(dataLookup) {
        // do something with returned data
    }
})

Inherits from

OpenLayers.Layer.XYZ

Summary

OpenLayers. Layer. UTFGrid	This Layer reads from UTFGrid tiled data sources.
Properties
isBaseLayer	Default is false, as UTFGrids are designed to be a transparent overlay layer.
projection	{OpenLayers.Projection} Source projection for the UTFGrids.
url	{String} URL tempate for UTFGrid tiles.
utfgridResolution	{Number} Ratio of the pixel width to the width of a UTFGrid data point.
Constructor
OpenLayers. Layer. UTFGrid	Create a new UTFGrid layer.
Functions and Properties
clone	Create a clone of this layer
getFeatureInfo	Get details about a feature associated with a map location.
getFeatureId	Get the identifier for the feature associated with a map location.

Properties

isBaseLayer

Default is false, as UTFGrids are designed to be a transparent overlay layer.

projection

{OpenLayers.Projection} Source projection for the UTFGrids. Default is “EPSG:900913”.

url

{String} URL tempate for UTFGrid tiles. Include x, y, and z parameters. E.g. “/tiles/${z}/${x}/${y}.json”

utfgridResolution

{Number} Ratio of the pixel width to the width of a UTFGrid data point. If an entry in the grid represents a 4x4 block of pixels, the utfgridResolution would be 4. Default is 2 (specified in OpenLayers.Tile.UTFGrid).

Constructor

OpenLayers. Layer. UTFGrid

Create a new UTFGrid layer.

Parameters

config

{Object} Configuration properties for the layer.

Required configuration properties

url	{String} The url template for UTFGrid tiles. See the url property.

Functions and Properties

clone

clone: function ( obj )

Create a clone of this layer

Parameters

obj	{Object} Only used by a subclass of this layer.

Returns

{OpenLayers.Layer.UTFGrid} An exact clone of this OpenLayers.Layer.UTFGrid

getFeatureInfo

Get details about a feature associated with a map location. The object returned will have id and data properties. If the given location doesn’t correspond to a feature, null will be returned.

Parameters

location

{OpenLayers.LonLat} map location

Returns

{Object} Object representing the feature id and UTFGrid data corresponding to the given map location. Returns null if the given location doesn’t hit a feature.

getFeatureId

getFeatureId: function( location )

Get the identifier for the feature associated with a map location.

Parameters

location

{OpenLayers.LonLat} map location

Returns

{String} The feature identifier corresponding to the given map location. Returns null if the location doesn’t hit a feature.