1
0
mirror of https://github.com/wavded/js-shapefile-to-geojson synced 2024-11-23 22:44:56 +00:00
js-shapefile-to-geojson/shapefile.js

325 lines
9.7 KiB
JavaScript
Raw Normal View History

2011-05-04 17:19:55 +00:00
(function(window,undefined){
if(window.document && window.Worker){
var worker = new Worker("shapefile.js")
var Shapefile = function(o, callback){
var
w = this.worker = worker,
t = this,
o = typeof o == "string" ? {shp: o} : o
w.onmessage = function(e){
t.data = e.date
if(callback) callback(e.data)
}
w.postMessage(["Load", o])
if(o.dbf) this.dbf = new DBF(o.dbf,function(data){
w.postMessage(["Add DBF Attributes", data])
})
}
window["Shapefile"] = Shapefile
return
}
var IN_WORKER = !window.document
if (IN_WORKER) {
importScripts('stream.js')
onmessage = function(e){
switch (e.data[0]) {
case "Load":
window.shapefile = new Shapefile(e.data[1])
break
case "Add DBF Attributes":
window.shapefile.addDBFDataToGeoJSON(e.data[1])
window.shapefile._postMessage()
break
default:
}
};
}
var SHAPE_TYPES = {
"0": "Null Shape",
"1": "Point", // standard shapes
"3": "PolyLine",
"5": "Polygon",
"8": "MultiPoint",
"11": "PointZ", // 3d shapes
"13": "PolyLineZ",
"15": "PolygonZ",
"18": "MultiPointZ",
"21": "PointM", // user-defined measurement shapes
"23": "PolyLineM",
"25": "PolygonM",
"28": "MultiPointM",
"31": "MultiPatch"
}
var Shapefile = function(o,callback){
var xhr = new XMLHttpRequest(),
that = this,
o = typeof o == "string" ? {shp: o} : o
xhr.open("GET", o.shp, false)
xhr.overrideMimeType("text/plain; charset=x-user-defined")
xhr.send()
if(200 != xhr.status)
throw "Unable to load " + o.shp + " status: " + xhr.status
this.url = o.shp
this.stream = new Gordon.Stream(xhr.responseText)
this.callback = callback
this.readFileHeader()
this.readRecords()
this.formatIntoGeoJson()
if(o.dbf) this.dbf = IN_WORKER ?
null :
new DBF(o.dbf,function(data){
that.addDBFDataToGeoJSON(data)
that._postMessage()
})
else this._postMessage
}
Shapefile.prototype = {
constructor: Shapefile,
_postMessage: function() {
var data = {
header: this.header,
records: this.records,
dbf: this.dbf,
geojson: this.geojson
}
if (IN_WORKER) postMessage(data)
else if (this.callback) this.callback(data)
},
readFileHeader: function(){
var s = this.stream,
header = this.header = {}
// The main file header is fixed at 100 bytes in length
if(s < 100) throw "Invalid Header Length"
// File code (always hex value 0x0000270a)
header.fileCode = s.readSI32(true)
if(header.fileCode != parseInt(0x0000270a))
throw "Invalid File Code"
// Unused; five uint32
s.offset += 4 * 5
// File length (in 16-bit words, including the header)
header.fileLength = s.readSI32(true) * 2
header.version = s.readSI32()
header.shapeType = SHAPE_TYPES[s.readSI32()]
// 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
this._readBounds(header)
// Z axis range
header.rangeZ = {
min: s.readDouble(),
max: s.readDouble()
}
// User defined measurement range
header.rangeM = {
min: s.readDouble(),
max: s.readDouble()
}
},
readRecords: function(){
var s = this.stream,
records = this.records = [],
record
do {
record = {}
// Record number (1-based)
record.id = s.readSI32(true)
if(record.id == 0) break //no more records
// Record length (in 16-bit words)
record.length = s.readSI32(true) * 2
record.shapeType = SHAPE_TYPES[s.readSI32()]
// Read specific shape
this["_read" + record.shapeType](record);
records.push(record);
} while(true);
},
_readBounds: function(object){
var s = this.stream
object.bounds = {
left: s.readDouble(),
bottom: s.readDouble(),
right: s.readDouble(),
top: s.readDouble()
}
return object
},
_readParts: function(record){
var s = this.stream,
nparts,
parts = []
nparts = record.numParts = s.readSI32()
// since number of points always proceeds number of parts, capture it now
record.numPoints = s.readSI32()
// parts array indicates at which index the next part starts at
while(nparts--) parts.push(s.readSI32())
record.parts = parts
return record
},
_readPoint: function(record){
var s = this.stream
record.x = s.readDouble()
record.y = s.readDouble()
return record
},
_readPoints: function(record){
var s = this.stream,
points = [],
npoints = record.numPoints || (record.numPoints = s.readSI32())
while(npoints--)
points.push({
x: s.readDouble(),
y: s.readDouble()
})
record.points = points
return record
},
_readMultiPoint: function(record){
var s = this.stream
this._readBounds(record)
this._readPoints(record)
return record
},
_readPolygon: function(record){
var s = this.stream
this._readBounds(record)
this._readParts(record)
this._readPoints(record)
return record
},
_readPolyLine: function(record){
return this._readPolygon(record);
},
formatIntoGeoJson: function(){
var bounds = this.header.bounds,
records = this.records,
features = [],
feature, geometry, points, fbounds, gcoords, parts, point,
geojson = {}
geojson.type = "FeatureCollection"
geojson.bbox = [
bounds.left,
bounds.bottom,
bounds.right,
bounds.top
]
geojson.features = features
for (var r = 0, record; record = records[r]; r++){
feature = {}, fbounds = record.bounds, points = record.points, parts = record.parts
feature.type = "Feature"
feature.bbox = [
fbounds.left,
fbounds.bottom,
fbounds.right,
fbounds.top
]
geometry = feature.geometry = {}
switch (record.shapeType) {
case "Point":
geometry.type = "Point"
geometry.coordinates = [
record.points.x,
record.points,y ]
break
case "MultiPoint":
case "PolyLine":
geometry.type = (record.shapeType == "PolyLine" ? "LineString" : "MultiPoint")
gcoords = geometry.coordinates = []
for (var p = 0; p < points.length; p++){
var point = points[p]
gcoords.push([point.x,point.y])
}
break
case "Polygon":
geometry.type = "Polygon"
gcoords = geometry.coordinates = []
for (var pt = 0; pt < parts.length; pt++){
var partIndex = parts[pt],
part = [],
point
// partIndex 0 == main poly, partIndex > 0 == holes in poly
for (var p = partIndex; p < (parts[pt+1] || points.length); p++){
point = points[p]
part.push([point.x,point.y])
}
gcoords.push(part)
}
break
default:
}
features.push(feature)
}
this.geojson = geojson
if(this._addDataAfterLoad) this.addDBFDataToGeoJSON(this._addDataAfterLoad);
},
addDBFDataToGeoJSON: function(dbfData){
if(!this.geojson) return (this._addDataAfterLoad = dbfData)
this.dbf = dbfData
var features = this.geojson.features,
len = features.length,
records = dbfData.records
while(len--) features[len].properties = records[len]
}
}
window["Shapefile"] = Shapefile;
})(self)