/* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for
* full list of contributors). Published under the Clear BSD license.
* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
* full text of the license. */
/**
* @requires OpenLayers/Format/JSON.js
* @requires OpenLayers/Feature/Vector.js
* @requires OpenLayers/Geometry/Point.js
* @requires OpenLayers/Geometry/MultiPoint.js
* @requires OpenLayers/Geometry/LineString.js
* @requires OpenLayers/Geometry/MultiLineString.js
* @requires OpenLayers/Geometry/Polygon.js
* @requires OpenLayers/Geometry/MultiPolygon.js
* @requires OpenLayers/Console.js
*/
/**
* Class: OpenLayers.Format.GeoJSON
* Read and write GeoJSON. Create a new parser with the
* <OpenLayers.Format.GeoJSON> constructor.
*
* Inherits from:
* - <OpenLayers.Format.JSON>
*/
OpenLayers.Format.GeoJSON = OpenLayers.Class(OpenLayers.Format.JSON, {
/**
* APIProperty: ignoreExtraDims
* {Boolean} Ignore dimensions higher than 2 when reading geometry
* coordinates.
*/
ignoreExtraDims: false,
/**
* Constructor: OpenLayers.Format.GeoJSON
* Create a new parser for GeoJSON.
*
* Parameters:
* options - {Object} An optional object whose properties will be set on
* this instance.
*/
initialize: function(options) {
OpenLayers.Format.JSON.prototype.initialize.apply(this, [options]);
},
/**
* APIMethod: read
* Deserialize a GeoJSON string.
*
* Parameters:
* json - {String} A GeoJSON string
* type - {String} Optional string that determines the structure of
* the output. Supported values are "Geometry", "Feature", and
* "FeatureCollection". If absent or null, a default of
* "FeatureCollection" is assumed.
* filter - {Function} A function which will be called for every key and
* value at every level of the final result. Each value will be
* replaced by the result of the filter function. This can be used to
* reform generic objects into instances of classes, or to transform
* date strings into Date objects.
*
* Returns:
* {Object} The return depends on the value of the type argument. If type
* is "FeatureCollection" (the default), the return will be an array
* of <OpenLayers.Feature.Vector>. If type is "Geometry", the input json
* must represent a single geometry, and the return will be an
* <OpenLayers.Geometry>. If type is "Feature", the input json must
* represent a single feature, and the return will be an
* <OpenLayers.Feature.Vector>.
*/
read: function(json, type, filter) {
type = (type) ? type : "FeatureCollection";
var results = null;
var obj = null;
if (typeof json == "string") {
obj = OpenLayers.Format.JSON.prototype.read.apply(this,
[json, filter]);
} else {
obj = json;
}
if(!obj) {
OpenLayers.Console.error("Bad JSON: " + json);
} else if(typeof(obj.type) != "string") {
OpenLayers.Console.error("Bad GeoJSON - no type: " + json);
} else if(this.isValidType(obj, type)) {
switch(type) {
case "Geometry":
try {
results = this.parseGeometry(obj);
} catch(err) {
OpenLayers.Console.error(err);
}
break;
case "Feature":
try {
results = this.parseFeature(obj);
results.type = "Feature";
} catch(err) {
OpenLayers.Console.error(err);
}
break;
case "FeatureCollection":
// for type FeatureCollection, we allow input to be any type
results = [];
switch(obj.type) {
case "Feature":
try {
results.push(this.parseFeature(obj));
} catch(err) {
results = null;
OpenLayers.Console.error(err);
}
break;
case "FeatureCollection":
for(var i=0, len=obj.features.length; i<len; ++i) {
try {
results.push(this.parseFeature(obj.features[i]));
} catch(err) {
results = null;
OpenLayers.Console.error(err);
}
}
break;
default:
try {
var geom = this.parseGeometry(obj);
results.push(new OpenLayers.Feature.Vector(geom));
} catch(err) {
results = null;
OpenLayers.Console.error(err);
}
}
break;
}
}
return results;
},
/**
* Method: isValidType
* Check if a GeoJSON object is a valid representative of the given type.
*
* Returns:
* {Boolean} The object is valid GeoJSON object of the given type.
*/
isValidType: function(obj, type) {
var valid = false;
switch(type) {
case "Geometry":
if(OpenLayers.Util.indexOf(
["Point", "MultiPoint", "LineString", "MultiLineString",
"Polygon", "MultiPolygon", "Box", "GeometryCollection"],
obj.type) == -1) {
// unsupported geometry type
OpenLayers.Console.error("Unsupported geometry type: " +
obj.type);
} else {
valid = true;
}
break;
case "FeatureCollection":
// allow for any type to be converted to a feature collection
valid = true;
break;
default:
// for Feature types must match
if(obj.type == type) {
valid = true;
} else {
OpenLayers.Console.error("Cannot convert types from " +
obj.type + " to " + type);
}
}
return valid;
},
/**
* Method: parseFeature
* Convert a feature object from GeoJSON into an
* <OpenLayers.Feature.Vector>.
*
* Parameters:
* obj - {Object} An object created from a GeoJSON object
*
* Returns:
* {<OpenLayers.Feature.Vector>} A feature.
*/
parseFeature: function(obj) {
var feature, geometry, attributes, bbox;
attributes = (obj.properties) ? obj.properties : {};
bbox = (obj.geometry && obj.geometry.bbox) || obj.bbox;
try {
geometry = this.parseGeometry(obj.geometry);
} catch(err) {
// deal with bad geometries
throw err;
}
feature = new OpenLayers.Feature.Vector(geometry, attributes);
if(bbox) {
feature.bounds = OpenLayers.Bounds.fromArray(bbox);
}
if(obj.id) {
feature.fid = obj.id;
}
return feature;
},
/**
* Method: parseGeometry
* Convert a geometry object from GeoJSON into an <OpenLayers.Geometry>.
*
* Parameters:
* obj - {Object} An object created from a GeoJSON object
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
parseGeometry: function(obj) {
if (obj == null) {
return null;
}
var geometry, collection = false;
if(obj.type == "GeometryCollection") {
if(!(obj.geometries instanceof Array)) {
throw "GeometryCollection must have geometries array: " + obj;
}
var numGeom = obj.geometries.length;
var components = new Array(numGeom);
for(var i=0; i<numGeom; ++i) {
components[i] = this.parseGeometry.apply(
this, [obj.geometries[i]]
);
}
geometry = new OpenLayers.Geometry.Collection(components);
collection = true;
} else {
if(!(obj.coordinates instanceof Array)) {
throw "Geometry must have coordinates array: " + obj;
}
if(!this.parseCoords[obj.type.toLowerCase()]) {
throw "Unsupported geometry type: " + obj.type;
}
try {
geometry = this.parseCoords[obj.type.toLowerCase()].apply(
this, [obj.coordinates]
);
} catch(err) {
// deal with bad coordinates
throw err;
}
}
// We don't reproject collections because the children are reprojected
// for us when they are created.
if (this.internalProjection && this.externalProjection && !collection) {
geometry.transform(this.externalProjection,
this.internalProjection);
}
return geometry;
},
/**
* Property: parseCoords
* Object with properties corresponding to the GeoJSON geometry types.
* Property values are functions that do the actual parsing.
*/
parseCoords: {
/**
* Method: parseCoords.point
* Convert a coordinate array from GeoJSON into an
* <OpenLayers.Geometry>.
*
* Parameters:
* array - {Object} The coordinates array from the GeoJSON fragment.
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
"point": function(array) {
if (this.ignoreExtraDims == false &&
array.length != 2) {
throw "Only 2D points are supported: " + array;
}
return new OpenLayers.Geometry.Point(array[0], array[1]);
},
/**
* Method: parseCoords.multipoint
* Convert a coordinate array from GeoJSON into an
* <OpenLayers.Geometry>.
*
* Parameters:
* array {Object} The coordinates array from the GeoJSON fragment.
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
"multipoint": function(array) {
var points = [];
var p = null;
for(var i=0, len=array.length; i<len; ++i) {
try {
p = this.parseCoords["point"].apply(this, [array[i]]);
} catch(err) {
throw err;
}
points.push(p);
}
return new OpenLayers.Geometry.MultiPoint(points);
},
/**
* Method: parseCoords.linestring
* Convert a coordinate array from GeoJSON into an
* <OpenLayers.Geometry>.
*
* Parameters:
* array - {Object} The coordinates array from the GeoJSON fragment.
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
"linestring": function(array) {
var points = [];
var p = null;
for(var i=0, len=array.length; i<len; ++i) {
try {
p = this.parseCoords["point"].apply(this, [array[i]]);
} catch(err) {
throw err;
}
points.push(p);
}
return new OpenLayers.Geometry.LineString(points);
},
/**
* Method: parseCoords.multilinestring
* Convert a coordinate array from GeoJSON into an
* <OpenLayers.Geometry>.
*
* Parameters:
* array - {Object} The coordinates array from the GeoJSON fragment.
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
"multilinestring": function(array) {
var lines = [];
var l = null;
for(var i=0, len=array.length; i<len; ++i) {
try {
l = this.parseCoords["linestring"].apply(this, [array[i]]);
} catch(err) {
throw err;
}
lines.push(l);
}
return new OpenLayers.Geometry.MultiLineString(lines);
},
/**
* Method: parseCoords.polygon
* Convert a coordinate array from GeoJSON into an
* <OpenLayers.Geometry>.
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
"polygon": function(array) {
var rings = [];
var r, l;
for(var i=0, len=array.length; i<len; ++i) {
try {
l = this.parseCoords["linestring"].apply(this, [array[i]]);
} catch(err) {
throw err;
}
r = new OpenLayers.Geometry.LinearRing(l.components);
rings.push(r);
}
return new OpenLayers.Geometry.Polygon(rings);
},
/**
* Method: parseCoords.multipolygon
* Convert a coordinate array from GeoJSON into an
* <OpenLayers.Geometry>.
*
* Parameters:
* array - {Object} The coordinates array from the GeoJSON fragment.
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
"multipolygon": function(array) {
var polys = [];
var p = null;
for(var i=0, len=array.length; i<len; ++i) {
try {
p = this.parseCoords["polygon"].apply(this, [array[i]]);
} catch(err) {
throw err;
}
polys.push(p);
}
return new OpenLayers.Geometry.MultiPolygon(polys);
},
/**
* Method: parseCoords.box
* Convert a coordinate array from GeoJSON into an
* <OpenLayers.Geometry>.
*
* Parameters:
* array - {Object} The coordinates array from the GeoJSON fragment.
*
* Returns:
* {<OpenLayers.Geometry>} A geometry.
*/
"box": function(array) {
if(array.length != 2) {
throw "GeoJSON box coordinates must have 2 elements";
}
return new OpenLayers.Geometry.Polygon([
new OpenLayers.Geometry.LinearRing([
new OpenLayers.Geometry.Point(array[0][0], array[0][1]),
new OpenLayers.Geometry.Point(array[1][0], array[0][1]),
new OpenLayers.Geometry.Point(array[1][0], array[1][1]),
new OpenLayers.Geometry.Point(array[0][0], array[1][1]),
new OpenLayers.Geometry.Point(array[0][0], array[0][1])
])
]);
}
},
/**
* APIMethod: write
* Serialize a feature, geometry, array of features into a GeoJSON string.
*
* Parameters:
* obj - {Object} An <OpenLayers.Feature.Vector>, <OpenLayers.Geometry>,
* or an array of features.
* pretty - {Boolean} Structure the output with newlines and indentation.
* Default is false.
*
* Returns:
* {String} The GeoJSON string representation of the input geometry,
* features, or array of features.
*/
write: function(obj, pretty) {
var geojson = {
"type": null
};
if(obj instanceof Array) {
geojson.type = "FeatureCollection";
var numFeatures = obj.length;
geojson.features = new Array(numFeatures);
for(var i=0; i<numFeatures; ++i) {
var element = obj[i];
if(!element instanceof OpenLayers.Feature.Vector) {
var msg = "FeatureCollection only supports collections " +
"of features: " + element;
throw msg;
}
geojson.features[i] = this.extract.feature.apply(
this, [element]
);
}
} else if (obj.CLASS_NAME.indexOf("OpenLayers.Geometry") == 0) {
geojson = this.extract.geometry.apply(this, [obj]);
} else if (obj instanceof OpenLayers.Feature.Vector) {
geojson = this.extract.feature.apply(this, [obj]);
if(obj.layer && obj.layer.projection) {
geojson.crs = this.createCRSObject(obj);
}
}
return OpenLayers.Format.JSON.prototype.write.apply(this,
[geojson, pretty]);
},
/**
* Method: createCRSObject
* Create the CRS object for an object.
*
* Parameters:
* object - {<OpenLayers.Feature.Vector>}
*
* Returns:
* {Object} An object which can be assigned to the crs property
* of a GeoJSON object.
*/
createCRSObject: function(object) {
var proj = object.layer.projection.toString();
var crs = {};
if (proj.match(/epsg:/i)) {
var code = parseInt(proj.substring(proj.indexOf(":") + 1));
if (code == 4326) {
crs = {
"type": "OGC",
"properties": {
"urn": "urn:ogc:def:crs:OGC:1.3:CRS84"
}
};
} else {
crs = {
"type": "EPSG",
"properties": {
"code": code
}
};
}
}
return crs;
},
/**
* Property: extract
* Object with properties corresponding to the GeoJSON types.
* Property values are functions that do the actual value extraction.
*/
extract: {
/**
* Method: extract.feature
* Return a partial GeoJSON object representing a single feature.
*
* Parameters:
* feature - {<OpenLayers.Feature.Vector>}
*
* Returns:
* {Object} An object representing the point.
*/
'feature': function(feature) {
var geom = this.extract.geometry.apply(this, [feature.geometry]);
return {
"type": "Feature",
"id": feature.fid == null ? feature.id : feature.fid,
"properties": feature.attributes,
"geometry": geom
};
},
/**
* Method: extract.geometry
* Return a GeoJSON object representing a single geometry.
*
* Parameters:
* geometry - {<OpenLayers.Geometry>}
*
* Returns:
* {Object} An object representing the geometry.
*/
'geometry': function(geometry) {
if (geometry == null) {
return null;
}
if (this.internalProjection && this.externalProjection) {
geometry = geometry.clone();
geometry.transform(this.internalProjection,
this.externalProjection);
}
var geometryType = geometry.CLASS_NAME.split('.')[2];
var data = this.extract[geometryType.toLowerCase()].apply(this, [geometry]);
var json;
if(geometryType == "Collection") {
json = {
"type": "GeometryCollection",
"geometries": data
};
} else {
json = {
"type": geometryType,
"coordinates": data
};
}
return json;
},
/**
* Method: extract.point
* Return an array of coordinates from a point.
*
* Parameters:
* point - {<OpenLayers.Geometry.Point>}
*
* Returns:
* {Array} An array of coordinates representing the point.
*/
'point': function(point) {
return [point.x, point.y];
},
/**
* Method: extract.multipoint
* Return an array of point coordinates from a multipoint.
*
* Parameters:
* multipoint - {<OpenLayers.Geometry.MultiPoint>}
*
* Returns:
* {Array} An array of point coordinate arrays representing
* the multipoint.
*/
'multipoint': function(multipoint) {
var array = [];
for(var i=0, len=multipoint.components.length; i<len; ++i) {
array.push(this.extract.point.apply(this, [multipoint.components[i]]));
}
return array;
},
/**
* Method: extract.linestring
* Return an array of coordinate arrays from a linestring.
*
* Parameters:
* linestring - {<OpenLayers.Geometry.LineString>}
*
* Returns:
* {Array} An array of coordinate arrays representing
* the linestring.
*/
'linestring': function(linestring) {
var array = [];
for(var i=0, len=linestring.components.length; i<len; ++i) {
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, len=multilinestring.components.length; i<len; ++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, len=polygon.components.length; i<len; ++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, len=multipolygon.components.length; i<len; ++i) {
array.push(this.extract.polygon.apply(this, [multipolygon.components[i]]));
}
return array;
},
/**
* Method: extract.collection
* Return an array of geometries from a geometry collection.
*
* Parameters:
* collection - {<OpenLayers.Geometry.Collection>}
*
* Returns:
* {Array} An array of geometry objects representing the geometry
* collection.
*/
'collection': function(collection) {
var len = collection.components.length;
var array = new Array(len);
for(var i=0; i<len; ++i) {
array[i] = this.extract.geometry.apply(
this, [collection.components[i]]
);
}
return array;
}
},
CLASS_NAME: "OpenLayers.Format.GeoJSON"
});