ab73cc3f79
git-svn-id: http://svn.openlayers.org/trunk/openlayers@3994 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
645 lines
23 KiB
JavaScript
645 lines
23 KiB
JavaScript
/* Copyright (c) 2006 MetaCarta, Inc., published under a modified BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/repository-license.txt
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* for the full text of the license. */
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/**
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* @requires OpenLayers/Format/JSON.js
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*
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* Class: OpenLayers.Format.GeoJSON
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* Read and write GeoJSON. Create a new parser with the
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* <OpenLayers.Format.GeoJSON> constructor.
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*
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* Inherits from:
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* - <OpenLayers.Format.JSON>
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*/
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OpenLayers.Format.GeoJSON = OpenLayers.Class(OpenLayers.Format.JSON, {
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/**
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* Constructor: OpenLayers.Format.GeoJSON
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* Create a new parser for GeoJSON.
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*
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* Parameters:
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* options - {Object} An optional object whose properties will be set on
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* this instance.
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*/
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initialize: function(options) {
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OpenLayers.Format.JSON.prototype.initialize.apply(this, [options]);
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},
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/**
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* APIMethod: read
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* Deserialize a GeoJSON string.
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*
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* Parameters:
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* json - {String} A GeoJSON string
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* type - {String} Optional string that determines the structure of
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* the output. Supported values are "Geometry", "Feature",
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* "GeometryCollection", and "FeatureCollection". If absent or null,
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* a default of "FeatureCollection" is assumed.
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* filter - {Function} A function which will be called for every key and
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* value at every level of the final result. Each value will be
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* replaced by the result of the filter function. This can be used to
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* reform generic objects into instances of classes, or to transform
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* date strings into Date objects.
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*
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* Returns:
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* {Object} The return depends on the value of the type argument. If type
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* is "FeatureCollection" (the default), the return will be an array
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* of <OpenLayers.Feature.Vector>. If type is "Geometry", the input json
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* must represent a single geometry, and the return will be an
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* <OpenLayers.Geometry>. If type is "Feature", the input json must
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* represent a single feature, and the return will be an
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* <OpenLayers.Feature.Vector>. If type is "GeometryCollection", the
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* input json must represent a geometry collection, and the return will
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* be an array of <OpenLayers.Geometry>.
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*/
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read: function(json, type, filter) {
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type = (type) ? type : "FeatureCollection";
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var results = null;
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var obj = null;
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if (typeof json == "string") {
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obj = OpenLayers.Format.JSON.prototype.read.apply(this,
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[json, filter]);
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} else {
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obj = json;
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}
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if(!obj) {
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OpenLayers.Console.error("Bad JSON: " + json);
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} else if(typeof(obj.type) != "string") {
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OpenLayers.Console.error("Bad GeoJSON - no type: " + json);
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} else if(this.isValidType(obj, type)) {
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switch(type) {
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case "Geometry":
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try {
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results = this.parseGeometry(obj);
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} catch(err) {
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OpenLayers.Console.error(err);
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}
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break;
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case "Feature":
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try {
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results = this.parseFeature(obj);
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results.type = "Feature";
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} catch(err) {
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OpenLayers.Console.error(err);
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}
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break;
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case "GeometryCollection":
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results = [];
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for(var i=0; i<obj.members.length; ++i) {
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try {
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results.push(this.parseGeometry(obj.members[i]));
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} catch(err) {
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results = null;
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OpenLayers.Console.error(err);
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}
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}
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break;
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case "FeatureCollection":
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// for type FeatureCollection, we allow input to be any type
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results = [];
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switch(obj.type) {
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case "Feature":
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try {
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results.push(this.parseFeature(obj));
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} catch(err) {
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results = null;
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OpenLayers.Console.error(err);
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}
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break;
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case "FeatureCollection":
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for(var i=0; i<obj.members.length; ++i) {
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try {
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results.push(this.parseFeature(obj.members[i]));
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} catch(err) {
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results = null;
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OpenLayers.Console.error(err);
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}
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}
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break;
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case "GeometryCollection":
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for(var i=0; i<obj.members.length; ++i) {
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try {
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var geom = this.parseGeometry(obj.members[i]);
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results.push(new OpenLayers.Feature.Vector(geom));
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} catch(err) {
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results = null;
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OpenLayers.Console.error(err);
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}
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}
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break;
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default:
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try {
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var geom = this.parseGeometry(obj);
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results.push(new OpenLayers.Feature.Vector(geom));
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} catch(err) {
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results = null;
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OpenLayers.Console.error(err);
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}
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}
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break;
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}
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}
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return results;
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},
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/**
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* Method: isValidType
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* Check if a GeoJSON object is a valid representative of the given type.
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*
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* Returns:
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* {Boolean} The object is valid GeoJSON object of the given type.
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*/
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isValidType: function(obj, type) {
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var valid = false;
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switch(type) {
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case "Geometry":
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if(OpenLayers.Util.indexOf(["Point", "MultiPoint", "LineString",
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"MultiLineString", "Polygon",
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"MultiPolygon", "Box"], obj.type) == -1) {
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// unsupported geometry type
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OpenLayers.Console.error("Unsupported geometry type: " +
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obj.type);
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} else {
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valid = true;
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}
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break;
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case "FeatureCollection":
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// allow for any type to be converted to a feature collection
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valid = true;
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break
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default:
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// for GeometryCollection and Feature, types must match
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if(obj.type == type) {
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valid = true;
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} else {
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OpenLayers.Console.error("Cannot convert types from " +
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obj.type + " to " + type);
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}
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}
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return valid;
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},
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/**
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* Method: parseFeature
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* Convert a feature object from GeoJSON into an
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* <OpenLayers.Feature.Vector>.
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*
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* Parameters:
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* obj - {Object} An object created from a GeoJSON object
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*
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* Returns:
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* {<OpenLayers.Feature.Vector>} A feature.
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*/
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parseFeature: function(obj) {
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var feature, geometry, attributes;
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attributes = (obj.properties) ? obj.properties : {};
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try {
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geometry = this.parseGeometry(obj.geometry);
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} catch(err) {
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// deal with bad geometries
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throw err;
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}
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feature = new OpenLayers.Feature.Vector(geometry, attributes);
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if(obj.id) {
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feature.fid = obj.id;
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}
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return feature;
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},
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/**
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* Method: parseGeometry
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* Convert a geometry object from GeoJSON into an <OpenLayers.Geometry>.
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*
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* Parameters:
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* obj - {Object} An object created from a GeoJSON object
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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parseGeometry: function(obj) {
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var geometry;
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if(!(obj.coordinates instanceof Array)) {
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throw "Geometry must have coordinates array: " + obj;
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}
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if(!this.parseCoords[obj.type.toLowerCase()]) {
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throw "Unsupported geometry type: " + obj.type;
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}
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try {
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geometry = this.parseCoords[obj.type.toLowerCase()].apply(this, [obj.coordinates]);
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} catch(err) {
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// deal with bad coordinates
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throw err;
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}
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return geometry;
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},
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/**
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* Property: parseCoords
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* Object with properties corresponding to the GeoJSON geometry types.
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* Property values are functions that do the actual parsing.
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*/
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parseCoords: {
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/**
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* Method: parseCoords.point
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* Convert a coordinate array from GeoJSON into an
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* <OpenLayers.Geometry>.
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*
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* Parameters:
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* array - {Object} The coordinates array from the GeoJSON fragment.
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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"point": function(array) {
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if(array.length != 2) {
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throw "Only 2D points are supported: " + array;
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}
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return new OpenLayers.Geometry.Point(array[0], array[1]);
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},
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/**
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* Method: parseCoords.multipoint
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* Convert a coordinate array from GeoJSON into an
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* <OpenLayers.Geometry>.
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*
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* Parameters:
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* array {Object} The coordinates array from the GeoJSON fragment.
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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"multipoint": function(array) {
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var points = [];
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var p = null;
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for(var i=0; i<array.length; ++i) {
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try {
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p = this.parseCoords["point"].apply(this, [array[i]]);
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} catch(err) {
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throw err;
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}
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points.push(p);
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}
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return new OpenLayers.Geometry.MultiPoint(points);
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},
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/**
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* Method: parseCoords.linestring
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* Convert a coordinate array from GeoJSON into an
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* <OpenLayers.Geometry>.
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*
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* Parameters:
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* array - {Object} The coordinates array from the GeoJSON fragment.
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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"linestring": function(array) {
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var points = [];
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var p = null;
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for(var i=0; i<array.length; ++i) {
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try {
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p = this.parseCoords["point"].apply(this, [array[i]]);
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} catch(err) {
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throw err;
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}
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points.push(p);
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}
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return new OpenLayers.Geometry.LineString(points);
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},
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/**
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* Method: parseCoords.multilinestring
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* Convert a coordinate array from GeoJSON into an
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* <OpenLayers.Geometry>.
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*
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* Parameters:
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* array - {Object} The coordinates array from the GeoJSON fragment.
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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"multilinestring": function(array) {
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var lines = [];
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var l = null;
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for(var i=0; i<array.length; ++i) {
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try {
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l = this.parseCoords["linestring"].apply(this, [array[i]]);
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} catch(err) {
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throw err;
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}
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lines.push(l);
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}
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return new OpenLayers.Geometry.MultiLineString(lines);
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},
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/**
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* Method: parseCoords.polygon
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* Convert a coordinate array from GeoJSON into an
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* <OpenLayers.Geometry>.
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*
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* Returns:
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* array - {Object} The coordinates array from the GeoJSON fragment.
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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"polygon": function(array) {
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var rings = [];
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var r, l;
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for(var i=0; i<array.length; ++i) {
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try {
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l = this.parseCoords["linestring"].apply(this, [array[i]]);
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} catch(err) {
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throw err;
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}
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r = new OpenLayers.Geometry.LinearRing(l.components);
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rings.push(r);
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}
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return new OpenLayers.Geometry.Polygon(rings);
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},
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/**
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* Method: parseCoords.multipolygon
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* Convert a coordinate array from GeoJSON into an
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* <OpenLayers.Geometry>.
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*
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* Parameters:
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* array - {Object} The coordinates array from the GeoJSON fragment.
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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"multipolygon": function(array) {
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var polys = [];
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var p = null;
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for(var i=0; i<array.length; ++i) {
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try {
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p = this.parseCoords["polygon"].apply(this, [array[i]]);
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} catch(err) {
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throw err;
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}
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polys.push(p);
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}
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return new OpenLayers.Geometry.MultiPolygon(polys);
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},
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/**
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* Method: parseCoords.box
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* Convert a coordinate array from GeoJSON into an
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* <OpenLayers.Geometry>.
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*
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* Parameters:
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* array - {Object} The coordinates array from the GeoJSON fragment.
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*
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* Returns:
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* {<OpenLayers.Geometry>} A geometry.
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*/
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"box": function(array) {
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if(array.length != 2) {
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throw "GeoJSON box coordinates must have 2 elements";
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}
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return new OpenLayers.Geometry.Polygon([
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new OpenLayers.Geometry.LinearRing([
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new OpenLayers.Geometry.Point(array[0][0], array[0][1]),
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new OpenLayers.Geometry.Point(array[1][0], array[0][1]),
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new OpenLayers.Geometry.Point(array[1][0], array[1][1]),
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new OpenLayers.Geometry.Point(array[0][0], array[1][1]),
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new OpenLayers.Geometry.Point(array[0][0], array[0][1])
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])
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]);
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}
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},
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/**
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* APIMethod: write
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* Serialize a feature, geometry, array of features, or array of geometries
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* into a GeoJSON string.
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*
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* Parameters:
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* obj - {Object} An <OpenLayers.Feature.Vector>, <OpenLayers.Geometry>,
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* or an array of either features or geometries.
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* pretty - {Boolean} Structure the output with newlines and indentation.
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* Default is false.
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*
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* Returns:
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* {String} The GeoJSON string representation of the input geometry,
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* features, array of geometries, or array of features.
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*/
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write: function(obj, pretty) {
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var geojson = {
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"type": null
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};
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if(obj instanceof Array) {
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geojson.members = [];
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for(var i=0; i<obj.length; ++i) {
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var element = obj[i];
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if(element instanceof OpenLayers.Feature.Vector) {
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if(geojson.type == null) {
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geojson.type = "FeatureCollection";
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if(element.layer && element.layer.projection) {
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var proj = element.layer.projection;
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if(proj.match(/epsg:/i)) {
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geojson.crs = {
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"type": "EPSG",
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"properties": {
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"code": parseInt(proj.substring(proj.indexOf(":") + 1))
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}
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};
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}
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}
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} else if(geojson.type != "FeatureCollection") {
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OpenLayers.Console.error("FeatureCollection only supports collections of features: " + element);
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break;
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}
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geojson.members.push(this.extract.feature.apply(this, [element]));
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} else if (element.CLASS_NAME.search("OpenLayers.Geometry") == 0) {
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if(geojson.type == null) {
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geojson.type = "GeometryCollection";
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} else if(geojson.type != "GeometryCollection") {
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OpenLayers.Console.error("GeometryCollection only supports collections of geometries: " + element);
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break;
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}
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geojson.members.push(this.extract.geometry.apply(this, [element]));
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}
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}
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} else if (obj.CLASS_NAME.search("OpenLayers.Geometry") == 0) {
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geojson = this.extract.geometry.apply(this, [obj]);
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} else if (obj instanceof OpenLayers.Feature.Vector) {
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geojson = this.extract.feature.apply(this, [obj]);
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if(obj.layer && obj.layer.projection) {
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var proj = obj.layer.projection;
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if(proj.match(/epsg:/i)) {
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geojson.crs = {
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"type": "EPSG",
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"properties": {
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"code": parseInt(proj.substring(proj.indexOf(":") + 1))
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}
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};
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}
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}
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}
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return OpenLayers.Format.JSON.prototype.write.apply(this,
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[geojson, pretty]);
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},
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/**
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* Property: extract
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* Object with properties corresponding to the GeoJSON types.
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* Property values are functions that do the actual value extraction.
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*/
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extract: {
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/**
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* Method: extract.feature
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* Return a partial GeoJSON object representing a single feature.
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*
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* Parameters:
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* feature - {<OpenLayers.Feature.Vector>}
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*
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* Returns:
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* {Object} An object representing the point.
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*/
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'feature': function(feature) {
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var geom = this.extract.geometry.apply(this, [feature.geometry]);
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return {
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"type": "Feature",
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"id": feature.fid == null ? feature.id : feature.fid,
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"properties": feature.attributes,
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"geometry": geom
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}
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},
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/**
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* Method: extract.geometry
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* Return a GeoJSON object representing a single geometry.
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*
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* Parameters:
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* geometry - {<OpenLayers.Geometry>}
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*
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* Returns:
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* {Object} An object representing the geometry.
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*/
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'geometry': function(geometry) {
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var geometryType = geometry.CLASS_NAME.split('.')[2];
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var data = this.extract[geometryType.toLowerCase()].apply(this, [geometry]);
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return {
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"type": geometryType,
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"coordinates": data
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}
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},
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/**
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* Method: extract.poin
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* Return an array of coordinates from a point.
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*
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* Parameters:
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* point - {<OpenLayers.Geometry.Point>}
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*
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* Returns:
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* {Array} An array of coordinates representing the point.
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*/
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'point': function(point) {
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return [point.x, point.y];
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},
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/**
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* Method: extract.multipoint
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|
* Return an array of point coordinates from a multipoint.
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|
*
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|
* Parameters:
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|
* multipoint - {<OpenLayers.Geometry.MultiPoint>}
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|
*
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|
* Returns:
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|
* {Array} An array of point coordinate arrays representing
|
|
* the multipoint.
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|
*/
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|
'multipoint': function(multipoint) {
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var array = [];
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for(var i=0; i<multipoint.components.length; ++i) {
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array.push(this.extract.point.apply(this, [multipoint.components[i]]));
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|
}
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|
return array;
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|
},
|
|
|
|
/**
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|
* Method: extract.linestring
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|
* Return an array of coordinate arrays from a linestring.
|
|
*
|
|
* Parameters:
|
|
* linestring - {<OpenLayers.Geometry.LineString>}
|
|
*
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|
* Returns:
|
|
* {Array} An array of coordinate arrays representing
|
|
* the linestring.
|
|
*/
|
|
'linestring': function(linestring) {
|
|
var array = [];
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|
for(var i=0; i<linestring.components.length; ++i) {
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|
array.push(this.extract.point.apply(this, [linestring.components[i]]));
|
|
}
|
|
return array;
|
|
},
|
|
|
|
/**
|
|
* Method: extract.multilinestring
|
|
* Return an array of linestring arrays from a linestring.
|
|
*
|
|
* Parameters:
|
|
* linestring - {<OpenLayers.Geometry.MultiLineString>}
|
|
*
|
|
* Returns:
|
|
* {Array} An array of linestring arrays representing
|
|
* the multilinestring.
|
|
*/
|
|
'multilinestring': function(multilinestring) {
|
|
var array = [];
|
|
for(var i=0; i<multilinestring.components.length; ++i) {
|
|
array.push(this.extract.linestring.apply(this, [multilinestring.components[i]]));
|
|
}
|
|
return array;
|
|
},
|
|
|
|
/**
|
|
* Method: extract.polygon
|
|
* Return an array of linear ring arrays from a polygon.
|
|
*
|
|
* Parameters:
|
|
* polygon - {<OpenLayers.Geometry.Polygon>}
|
|
*
|
|
* Returns:
|
|
* {Array} An array of linear ring arrays representing the polygon.
|
|
*/
|
|
'polygon': function(polygon) {
|
|
var array = [];
|
|
for(var i=0; i<polygon.components.length; ++i) {
|
|
array.push(this.extract.linestring.apply(this, [polygon.components[i]]));
|
|
}
|
|
return array;
|
|
},
|
|
|
|
/**
|
|
* Method: extract.multipolygon
|
|
* Return an array of polygon arrays from a multipolygon.
|
|
*
|
|
* Parameters:
|
|
* multipolygon - {<OpenLayers.Geometry.MultiPolygon>}
|
|
*
|
|
* Returns:
|
|
* {Array} An array of polygon arrays representing
|
|
* the multipolygon
|
|
*/
|
|
'multipolygon': function(multipolygon) {
|
|
var array = [];
|
|
for(var i=0; i<multipolygon.components.length; ++i) {
|
|
array.push(this.extract.polygon.apply(this, [multipolygon.components[i]]));
|
|
}
|
|
return array;
|
|
}
|
|
|
|
},
|
|
|
|
CLASS_NAME: "OpenLayers.Format.GeoJSON"
|
|
|
|
});
|