mirror of
https://github.com/wavded/js-shapefile-to-geojson
synced 2024-11-23 14:34:54 +00:00
324 lines
9.6 KiB
JavaScript
324 lines
9.6 KiB
JavaScript
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(function(window,undefined){
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if(window.document && window.Worker){
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var worker = new Worker("shapefile.js")
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var Shapefile = function(o, callback){
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var
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w = this.worker = worker,
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t = this,
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o = typeof o == "string" ? {shp: o} : o
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w.onmessage = function(e){
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t.data = e.date
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if(callback) callback(e.data)
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}
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w.postMessage(["Load", o])
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if(o.dbf) this.dbf = new DBF(o.dbf,function(data){
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w.postMessage(["Add DBF Attributes", data])
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})
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}
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window["Shapefile"] = Shapefile
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return
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}
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var IN_WORKER = !window.document
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if (IN_WORKER) {
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importScripts('stream.js')
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onmessage = function(e){
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switch (e.data[0]) {
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case "Load":
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window.shapefile = new Shapefile(e.data[1])
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break
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case "Add DBF Attributes":
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window.shapefile.addDBFDataToGeoJSON(e.data[1])
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window.shapefile._postMessage()
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break
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default:
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}
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};
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}
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var SHAPE_TYPES = {
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"0": "Null Shape",
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"1": "Point", // standard shapes
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"3": "PolyLine",
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"5": "Polygon",
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"8": "MultiPoint",
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"11": "PointZ", // 3d shapes
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"13": "PolyLineZ",
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"15": "PolygonZ",
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"18": "MultiPointZ",
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"21": "PointM", // user-defined measurement shapes
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"23": "PolyLineM",
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"25": "PolygonM",
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"28": "MultiPointM",
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"31": "MultiPatch"
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}
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var Shapefile = function(o,callback){
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var xhr = new XMLHttpRequest(),
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that = this,
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o = typeof o == "string" ? {shp: o} : o
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xhr.open("GET", o.shp, false)
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xhr.overrideMimeType("text/plain; charset=x-user-defined")
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xhr.send()
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if(200 != xhr.status)
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throw "Unable to load " + o.shp + " status: " + xhr.status
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this.url = o.shp
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this.stream = new Gordon.Stream(xhr.responseText)
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this.callback = callback
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this.readFileHeader()
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this.readRecords()
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this.formatIntoGeoJson()
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if(o.dbf) this.dbf = IN_WORKER ?
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null :
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new DBF(o.dbf,function(data){
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that.addDBFDataToGeoJSON(data)
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that._postMessage()
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})
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else this._postMessage
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}
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Shapefile.prototype = {
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constructor: Shapefile,
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_postMessage: function() {
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var data = {
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header: this.header,
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records: this.records,
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dbf: this.dbf,
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geojson: this.geojson
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}
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if (IN_WORKER) postMessage(data)
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else if (this.callback) this.callback(data)
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},
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readFileHeader: function(){
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var s = this.stream,
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header = this.header = {}
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// The main file header is fixed at 100 bytes in length
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if(s < 100) throw "Invalid Header Length"
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// File code (always hex value 0x0000270a)
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header.fileCode = s.readSI32(true)
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if(header.fileCode != parseInt(0x0000270a))
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throw "Invalid File Code"
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// Unused; five uint32
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s.offset += 4 * 5
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// File length (in 16-bit words, including the header)
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header.fileLength = s.readSI32(true) * 2
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header.version = s.readSI32()
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header.shapeType = SHAPE_TYPES[s.readSI32()]
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// Minimum bounding rectangle (MBR) of all shapes contained within the shapefile; four doubles in the following order: min X, min Y, max X, max Y
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this._readBounds(header)
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// Z axis range
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header.rangeZ = {
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min: s.readDouble(),
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max: s.readDouble()
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}
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// User defined measurement range
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header.rangeM = {
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min: s.readDouble(),
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max: s.readDouble()
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}
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},
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readRecords: function(){
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var s = this.stream,
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records = this.records = [],
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record
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do {
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record = {}
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// Record number (1-based)
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record.id = s.readSI32(true)
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if(record.id == 0) break //no more records
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// Record length (in 16-bit words)
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record.length = s.readSI32(true) * 2
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record.shapeType = SHAPE_TYPES[s.readSI32()]
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// Read specific shape
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this["_read" + record.shapeType](record);
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records.push(record);
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} while(true);
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},
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_readBounds: function(object){
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var s = this.stream
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object.bounds = {
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left: s.readDouble(),
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bottom: s.readDouble(),
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right: s.readDouble(),
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top: s.readDouble()
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}
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return object
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},
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_readParts: function(record){
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var s = this.stream,
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nparts,
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parts = []
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nparts = record.numParts = s.readSI32()
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// since number of points always proceeds number of parts, capture it now
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record.numPoints = s.readSI32()
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// parts array indicates at which index the next part starts at
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while(nparts--) parts.push(s.readSI32())
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record.parts = parts
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return record
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},
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_readPoint: function(record){
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var s = this.stream
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record.x = s.readDouble()
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record.y = s.readDouble()
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return record
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},
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_readPoints: function(record){
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var s = this.stream,
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points = [],
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npoints = record.numPoints || (record.numPoints = s.readSI32())
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while(npoints--)
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points.push({
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x: s.readDouble(),
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y: s.readDouble()
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})
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record.points = points
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return record
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},
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_readMultiPoint: function(record){
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var s = this.stream
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this._readBounds(record)
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this._readPoints(record)
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return record
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},
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_readPolygon: function(record){
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var s = this.stream
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this._readBounds(record)
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this._readParts(record)
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this._readPoints(record)
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return record
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},
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_readPolyLine: function(record){
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return this._readPolygon(record);
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},
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formatIntoGeoJson: function(){
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var bounds = this.header.bounds,
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records = this.records,
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features = [],
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feature, geometry, points, fbounds, gcoords, parts, point,
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geojson = {}
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geojson.type = "FeatureCollection"
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geojson.bbox = [
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bounds.left,
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bounds.bottom,
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bounds.right,
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bounds.top
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]
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geojson.features = features
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for (var r = 0, record; record = records[r]; r++){
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feature = {}, fbounds = record.bounds, points = record.points, parts = record.parts
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feature.type = "Feature"
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feature.bbox = [
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fbounds.left,
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fbounds.bottom,
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fbounds.right,
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fbounds.top
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]
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geometry = feature.geometry = {}
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switch (record.shapeType) {
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case "Point":
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geometry.type = "Point"
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geometry.coordinates = [
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record.points.x,
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record.points,y ]
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break
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case "MultiPoint":
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case "PolyLine":
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geometry.type = (record.shapeType == "PolyLine" ? "LineString" : "MultiPoint")
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gcoords = geometry.coordinates = []
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for (var p = 0; p < points.length; p++){
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var point = points[p]
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gcoords.push([point.x,point.y])
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}
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break
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case "Polygon":
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geometry.type = "Polygon"
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gcoords = geometry.coordinates = []
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for (var pt = 0; pt < parts.length; pt++){
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var partIndex = parts[pt],
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part = [],
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point
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for (var p = partIndex; p < (partIndex[pt+1] || points.length); p++){
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point = points[p]
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part.push([point.x,point.y])
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}
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gcoords.push(part)
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}
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break
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default:
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}
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features.push(feature)
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}
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this.geojson = geojson
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if(this._addDataAfterLoad) this.addDBFDataToGeoJSON(this._addDataAfterLoad);
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},
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addDBFDataToGeoJSON: function(dbfData){
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if(!this.geojson) return (this._addDataAfterLoad = dbfData)
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this.dbf = dbfData
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var features = this.geojson.features,
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len = features.length,
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records = dbfData.records
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while(len--) features[len].properties = records[len]
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}
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}
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window["Shapefile"] = Shapefile;
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})(self)
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