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shp.js
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shp.js
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///
/// Author: YanzheZhang
/// Date: 25/3/2018
/// Desc:添加loadArrayBuffer
///
/// Revision History:
/// -----------------------------------
/// Author: http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf
/// Date:
/// Desc:Shapefile parser
SHP = {
NULL: 0,
POINT: 1,
POLYLINE: 3,
POLYGON: 5
};
SHP.getShapeName = function(id) {
for (name in this) {
if (id === this[name]) {
return name;
}
}
};
SHPParser = function() {
};
SHPParser.load = function(src, callback, onerror) {
//var xhr = new XMLHttpRequest();
/*
IE8/IE9、Opera Mini 完全不支持xhr对象
IE10/IE11部分支持,不支持 xhr.responseType为json
部分浏览器不支持设置请求超时,即无法使用xhr.timeout
部分浏览器不支持xhr.responseType为blob
*/
var xhr;
if (window.XMLHttpRequest)
{
xhr=new XMLHttpRequest();
}
else
{
xhr=new ActiveXObject("Microsoft.XMLHTTP");
}
xhr.responseType = 'arraybuffer';
xhr.onload = function() {
console.log(xhr.response);
var d = new SHPParser().parse(xhr.response);
callback(d);
};
xhr.onerror = onerror;
xhr.open('GET', src);
xhr.send(null);
};
SHPParser.loadArrayBuffer = function (arrayBuffer, callback, onerror) {
var d = new SHPParser().parse(arrayBuffer);
if (d) {
callback(d);
} else {
onerror();
}
}
SHPParser.prototype.parse = function(arrayBuffer) {
var o = {};
var dv = new DataView(arrayBuffer);
var idx = 0;//当前流位置
o.fileCode = dv.getInt32(idx, false);
if (o.fileCode != 0x0000270a) { //9994
throw (new Error("Unknown file code: " + o.fileCode));
}
idx += 6*4;
o.wordLength = dv.getInt32(idx, false);
o.byteLength = o.wordLength * 2;
idx += 4;
o.version = dv.getInt32(idx, true);
idx += 4;
o.shapeType = dv.getInt32(idx, true);
idx += 4;
o.minX = dv.getFloat64(idx, true);
o.minY = dv.getFloat64(idx+8, true);
o.maxX = dv.getFloat64(idx+16, true);
o.maxY = dv.getFloat64(idx+24, true);
o.minZ = dv.getFloat64(idx+32, true);
o.maxZ = dv.getFloat64(idx+40, true);
o.minM = dv.getFloat64(idx+48, true);
o.maxM = dv.getFloat64(idx+56, true);
idx += 8*8;
o.records = [];
while (idx < o.byteLength) {
var record = {};
record.number = dv.getInt32(idx, false);
idx += 4;
record.length = dv.getInt32(idx, false);
idx += 4;
try {
record.shape = this.parseShape(dv, idx, record.length);
} catch(e) {
console.log(e, record);
}
idx += record.length * 2;
o.records.push(record);
}
return o;
};
SHPParser.prototype.parseShape = function(dv, idx, length) {
var i=0, c=null;
var shape = {};
shape.type = dv.getInt32(idx, true);
idx += 4;
var byteLen = length * 2;
switch (shape.type) {
case SHP.NULL: // Null
break;
case SHP.POINT: // Point (x,y)
shape.content = {
x: dv.getFloat64(idx, true),
y: dv.getFloat64(idx+8, true)
};
break;
case SHP.POLYLINE: // Polyline (MBR, partCount, pointCount, parts, points)
case SHP.POLYGON: // Polygon (MBR, partCount, pointCount, parts, points)
c = shape.content = {
minX: dv.getFloat64(idx, true),
minY: dv.getFloat64(idx+8, true),
maxX: dv.getFloat64(idx+16, true),
maxY: dv.getFloat64(idx+24, true),
parts: new Int32Array(dv.getInt32(idx+32, true)),
points: new Float64Array(dv.getInt32(idx+36, true)*2)
};
idx += 40;
for (i=0; i<c.parts.length; i++) {
c.parts[i] = dv.getInt32(idx, true);
idx += 4;
}
for (i=0; i<c.points.length; i++) {
c.points[i] = dv.getFloat64(idx, true);
idx += 8;
}
break;
case 8: // MultiPoint (MBR, pointCount, points)
case 11: // PointZ (X, Y, Z, M)
case 13: // PolylineZ
case 15: // PolygonZ
case 18: // MultiPointZ
case 21: // PointM (X, Y, M)
case 23: // PolylineM
case 25: // PolygonM
case 28: // MultiPointM
case 31: // MultiPatch
throw new Error("Shape type not supported: "
+ shape.type + ':' +
+ SHP.getShapeName(shape.type));
default:
throw new Error("Unknown shape type at " + (idx-4) + ': ' + shape.type);
}
return shape;
};