Merge pull request #274 from tschaub/utfgrid
UTFGrid Tile, Layer, and Control. This adds support for responsive handling of interactions with large numbers of features represented by UTFGrids.
This commit is contained in:
Tim Schaub
@@ -419,6 +419,64 @@ OpenLayers.Layer.Grid = OpenLayers.Class(OpenLayers.Layer.HTTPRequest, {
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}
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}
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},
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/**
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* Method: getTileData
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* Given a map location, retrieve a tile and the pixel offset within that
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* tile corresponding to the location. If there is not an existing
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* tile in the grid that covers the given location, null will be
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* returned.
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*
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* Parameters:
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* loc - {<OpenLayers.LonLat>} map location
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*
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* Returns:
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* {Object} Object with the following properties: tile ({<OpenLayers.Tile>}),
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* i ({Number} x-pixel offset from top left), and j ({Integer} y-pixel
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* offset from top left).
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*/
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getTileData: function(loc) {
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var data = null,
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x = loc.lon,
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y = loc.lat,
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numRows = this.grid.length;
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if (this.map && numRows) {
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var res = this.map.getResolution(),
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tileWidth = this.tileSize.w,
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tileHeight = this.tileSize.h,
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bounds = this.grid[0][0].bounds,
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left = bounds.left,
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top = bounds.top;
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if (x < left) {
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// deal with multiple worlds
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if (this.map.baseLayer.wrapDateLine) {
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var worldWidth = this.map.getMaxExtent().getWidth();
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var worldsAway = Math.ceil((left - x) / worldWidth);
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x += worldWidth * worldsAway;
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}
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}
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// tile distance to location (fractional number of tiles);
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var dtx = (x - left) / (res * tileWidth);
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var dty = (top - y) / (res * tileHeight);
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// index of tile in grid
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var col = Math.floor(dtx);
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var row = Math.floor(dty);
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if (row >= 0 && row < numRows) {
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var tile = this.grid[row][col];
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if (tile) {
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data = {
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tile: tile,
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// pixel index within tile
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i: Math.floor((dtx - col) * tileWidth),
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j: Math.floor((dty - row) * tileHeight)
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};
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}
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}
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}
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return data;
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},
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/**
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* Method: queueTileDraw
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178
lib/OpenLayers/Layer/UTFGrid.js
Normal file
178
lib/OpenLayers/Layer/UTFGrid.js
Normal file
@@ -0,0 +1,178 @@
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/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
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* full list of contributors). Published under the Clear BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
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* full text of the license. */
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/**
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* @requires OpenLayers/Layer/XYZ.js
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* @requires OpenLayers/Tile/UTFGrid.js
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*/
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/**
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* Class: OpenLayers.Layer.UTFGrid
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* This Layer reads from UTFGrid tiled data sources. Since UTFGrids are
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* essentially JSON-based ASCII art with attached attributes, they are not
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* visibly rendered. In order to use them in the map, you must add a
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* <OpenLayers.Control.UTFGrid> ontrol as well.
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*
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* Example:
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*
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* (start code)
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* var world_utfgrid = new OpenLayers.Layer.UTFGrid({
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* url: "/tiles/world_utfgrid/${z}/${x}/${y}.json",
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* utfgridResolution: 4,
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* displayInLayerSwitcher: false
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* );
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* map.addLayer(world_utfgrid);
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*
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* var control = new OpenLayers.Control.UTFGrid({
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* layers: [world_utfgrid],
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* handlerMode: 'move',
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* callback: function(dataLookup) {
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* // do something with returned data
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* }
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* })
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* (end code)
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*
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*
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* Inherits from:
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* - <OpenLayers.Layer.XYZ>
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*/
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OpenLayers.Layer.UTFGrid = OpenLayers.Class(OpenLayers.Layer.XYZ, {
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/**
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* APIProperty: isBaseLayer
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* Default is true, as this is designed to be a base tile source.
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*/
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isBaseLayer: false,
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/**
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* APIProperty: projection
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* {<OpenLayers.Projection>}
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* Source projection for the UTFGrids. Default is "EPSG:900913".
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*/
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projection: new OpenLayers.Projection("EPSG:900913"),
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/**
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* Property: useJSONP
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* {Boolean}
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* Should we use a JSONP script approach instead of a standard AJAX call?
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*
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* Set to true for using utfgrids from another server.
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* Avoids same-domain policy restrictions.
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* Note that this only works if the server accepts
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* the callback GET parameter and dynamically
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* wraps the returned json in a function call.
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*
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* Default is false
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*/
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useJSONP: false,
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/**
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* APIProperty: url
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* {String}
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* URL tempate for UTFGrid tiles. Include x, y, and z parameters.
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* E.g. "/tiles/${z}/${x}/${y}.json"
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*/
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/**
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* APIProperty: utfgridResolution
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* {Number}
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* Ratio of the pixel width to the width of a UTFGrid data point. If an
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* entry in the grid represents a 4x4 block of pixels, the
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* utfgridResolution would be 4. Default is 2 (specified in
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* <OpenLayers.Tile.UTFGrid>).
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*/
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/**
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* Property: tileClass
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* {<OpenLayers.Tile>} The tile class to use for this layer.
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* Defaults is <OpenLayers.Tile.UTFGrid>.
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*/
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tileClass: OpenLayers.Tile.UTFGrid,
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/**
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* Constructor: OpenLayers.Layer.UTFGrid
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* Create a new UTFGrid layer.
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*
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* Parameters:
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* config - {Object} Configuration properties for the layer.
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*
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* Required configuration properties:
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* url - {String} The url template for UTFGrid tiles. See the <url> property.
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*/
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initialize: function(options) {
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OpenLayers.Layer.Grid.prototype.initialize.apply(
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this, [options.name, options.url, {}, options]
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);
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this.tileOptions = OpenLayers.Util.extend({
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utfgridResolution: this.utfgridResolution
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}, this.tileOptions);
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},
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/**
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* APIMethod: clone
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* Create a clone of this layer
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*
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* Parameters:
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* obj - {Object} Only used by a subclass of this layer.
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*
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* Returns:
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* {<OpenLayers.Layer.UTFGrid>} An exact clone of this OpenLayers.Layer.UTFGrid
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*/
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clone: function (obj) {
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if (obj == null) {
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obj = new OpenLayers.Layer.UTFGrid(this.getOptions());
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}
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// get all additions from superclasses
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obj = OpenLayers.Layer.Grid.prototype.clone.apply(this, [obj]);
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return obj;
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},
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/**
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* APIProperty: getFeatureInfo
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* Get details about a feature associated with a map location. The object
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* returned will have id and data properties. If the given location
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* doesn't correspond to a feature, null will be returned.
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*
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* Parameters:
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* location - {<OpenLayers.LonLat>} map location
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*
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* Returns:
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* {Object} Object representing the feature id and UTFGrid data
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* corresponding to the given map location. Returns null if the given
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* location doesn't hit a feature.
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*/
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getFeatureInfo: function(location) {
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var info = null;
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var tileInfo = this.getTileData(location);
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if (tileInfo.tile) {
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info = tileInfo.tile.getFeatureInfo(tileInfo.i, tileInfo.j);
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}
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return info;
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},
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/**
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* APIMethod: getFeatureId
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* Get the identifier for the feature associated with a map location.
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*
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* Parameters:
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* location - {<OpenLayers.LonLat>} map location
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*
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* Returns:
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* {String} The feature identifier corresponding to the given map location.
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* Returns null if the location doesn't hit a feature.
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*/
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getFeatureId: function(location) {
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var id = null;
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var info = this.getTileData(location);
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if (info.tile) {
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id = info.tile.getFeatureId(info.i, info.j);
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}
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return id;
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},
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CLASS_NAME: "OpenLayers.Layer.UTFGrid"
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});
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