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( function ( $ ) {
op2geojson = function() {
var instance = {},
geojson;
instance.fetch = function(url, data, zoom, callback) {
var postCallback = function(data) {
// Add nodes and ways to the layer
var features = [];
// Process the data
var nodes = {};
var ways = {};
var relations = {};
$.each(data.elements, function(i, item) {
if (item.type === 'node') {
nodes[item.id] = item;
// As the nodes do not relate to other bits,
// they can be added here
if (item.tags != undefined) {
features.push( instance.point(item) );
}
} else if (item.type === 'way') {
ways[item.id] = item;
} else if (item.type === 'relation') {
relations[item.id] = item;
}
});
$.each(ways, function(i, way) {
if (zoom < 16) {
var node = nodes[way.nodes[0]];
var point = {
type : "Feature",
id : way.id,
geometry : {
type : "Point",
coordinates : [node.lon,node.lat]
},
properties : {}
};
_.extend(point.properties, way.tags);
features.push(point);
} else {
features.push(instance.lineString(way, nodes));
}
});
$.each(relations, function(i, relation) {
if (relation.tags != undefined &&
relation.tags['type'] == 'boundary' &&
relation.tags['boundary'] == 'catchment_area') {
var poly = instance.polygon(relation, ways, nodes);
poly.id = relation.id;
features.push(poly);
}
});
geojson = instance.featureCollection(features);
callback(geojson);
}
$.post(url, data, postCallback, "json");
};
instance.point = function(node) {
var point = {
type : "Feature",
geometry : {
type : "Point",
coordinates : [node.lon,node.lat]
},
properties : {}
};
_.extend(point.properties, node.tags);
return point;
}
instance.lineString = function(way, nodeArray) {
// Get the node coordinates from nodeArray
var coordinates = [];
for (id in way.nodes) {
var node = nodeArray[way.nodes[id]];
coordinates.push([node.lon,node.lat]);
}
// Create the LineString
var lineString = {
type : "Feature",
geometry : {
type : "LineString",
coordinates : coordinates
},
properties : {}
};
// Add the tags
_.extend(lineString.properties, way.tags);
return lineString;
}
instance.featureCollection = function(features) {
collection = {
type : "FeatureCollection",
features : features
};
return collection;
}
instance.polygon = function(relation, ways, nodes) {
polyCoords = [];
var firstCheck = true;
var subject;
$.each(relation.members, function(i, member) {
if (member.role == "outer") {
var way = ways[member.ref];
if (typeof way == 'undefined') return;
var wayCoords = instance.lineString(way, nodes).geometry.coordinates;
var numNodes = wayCoords.length
// Need to ensure that the first way is in the correct direction, but this can
// only be checked when looking at the second way
if (firstCheck && polyCoords.length != 0) {
firstCheck = false;
if ((polyCoords[0][0] == wayCoords[0][0] &&
polyCoords[0][1] == wayCoords[0][1]) ||
(polyCoords[0][0] == wayCoords[numNodes - 1][0] &&
polyCoords[0][1] == wayCoords[numNodes - 1][1])) {
polyCoords.reverse();
}
}
if (polyCoords.length != 0) {
// If this way is backward
if (polyCoords[polyCoords.length - 1][0] != wayCoords[0][0] ||
polyCoords[polyCoords.length - 1][1] != wayCoords[0][1]) {
wayCoords.reverse();
}
polyCoords.pop();
}
polyCoords = polyCoords.concat( wayCoords );
} else if (member.role == "subject") {
subject = member.ref;
}
});
var poly = {
type : "Feature",
geometry : {
type : "Polygon",
coordinates : [polyCoords]
},
properties : {}
};
// Add the tags
_.extend(poly.properties, relation.tags);
poly.properties["subject"] = subject;
return poly;
}
return instance;
};
})( jQuery );
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