（转） Arcgis for js之WKT和GEOMETRY的相互转换 |
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http://blog.csdn.net/gisshixisheng/article/details/44057453 1、wkt简介 WKT(Well-known text)是一种文本标记语言，用于表示矢量几何对象、空间参照系统及空间参照系统之间的转换。它的二进制表示方式，亦即WKB(well-known-binary)则胜于在传输和在数据库中存储相同的信息。该格式由开放地理空间联盟(OGC)制定。WKT可以表示的几何对象包括：点，线，多边形，TIN（不规则三角网）及多面体。以下为几何WKT字串样例：POINT(6 10)LINESTRING(3 4,10 50,20 25)POLYGON((1 1,5 1,5 5,1 5,1 1),(2 2,2 3,3 3,3 2,2 2))MULTIPOINT(3.5 5.6, 4.8 10.5)MULTILINESTRING((3 4,10 50,20 25),(-5 -8,-10 -8,-15 -4))MULTIPOLYGON(((1 1,5 1,5 5,1 5,1 1),(2 2,2 3,3 3,3 2,2 2)),((6 3,9 2,9 4,6 3)))GEOMETRYCOLLECTION(POINT(4 6),LINESTRING(4 6,7 10))POINT ZM (1 1 5 60)POINT M (1 1 80)POINT EMPTYMULTIPOLYGON EMPTY 2、geometry geometry为Arcgis中的几何对象，包括Extent、Multipoint、Point 、Polygon 、Polyline。 3、相互转换 实现相互转换，封装成了两个js文件，内容如下： WKTUtil.js [javascript] view plain copy print? var WKTUtil = function(options){ this.initialize(options); } WKTUtil.prototype = { /** * Constructor: OpenLayers.Format.WKT * Create a new parser for WKT * * Parameters: * options - {Object} An optional object whose properties will be set on * this instance * * Returns: * {} A new WKT parser. */ initialize: function(options) { this.regExes = { 'typeStr': /^\s*(\w+)\s*\s∗(.∗)\s∗\s*$/, 'spaces': /\s+/, 'parenComma': /\)\s*,\s*\(/, 'doubleParenComma': /\)\s*\)\s*,\s*\(\s*\(/, // can't use {2} here 'trimParens': /^\s*?(.∗?)?\s*$/ }; for(var i in options){ this[i] = options[i]; } }, /** * APIMethod: read * Deserialize a WKT string and return a vector feature or an * array of vector features. Supports WKT for POINT, MULTIPOINT, * LINESTRING, MULTILINESTRING, POLYGON, MULTIPOLYGON, and * GEOMETRYCOLLECTION. * * Parameters: * wkt - {String} A WKT string * * Returns: * {|Array} A feature or array of features for * GEOMETRYCOLLECTION WKT. */ read: function(wkt) { var features, type, str; wkt = wkt.replace(/[\n\r]/g, " "); var matches = this.regExes.typeStr.exec(wkt); if(matches) { type = matches[1].toLowerCase(); str = matches[2]; if(this.parse[type]) { features = this.parse[type].apply(this, [str]); //console.log(features); } } return features; }, /** * Method: extractGeometry * Entry point to construct the WKT for a single Geometry object. * * Parameters: * geometry - {} * * Returns: * {String} A WKT string of representing the geometry */ extractGeometry: function(geometry) { var type = geometry.CLASS_NAME.split('.')[2].toLowerCase(); if (!this.extract[type]) { return null; } if (this.internalProjection && this.externalProjection) { geometry = geometry.clone(); geometry.transform(this.internalProjection, this.externalProjection); } var wktType = type == 'collection' ? 'GEOMETRYCOLLECTION' : type.toUpperCase(); var data = wktType + '(' + this.extract[type].apply(this, [geometry]) + ')'; return data; }, trim: function(str){ return str.replace(/^\s\s*/, '').replace(/\s\s*$/, ''); }, /** * Object with properties corresponding to the geometry types. * Property values are functions that do the actual parsing. */ parse: { /** * Return point feature given a point WKT fragment. * @param {String} str A WKT fragment representing the point * @returns {OpenLayers.Feature.Vector} A point feature * @private */ 'point': function(str) { var coords = this.trim(str).split(this.regExes.spaces); return coords;//new esri.geometry.Point(coords[0], coords[1]); }, /** * Return a multipoint feature given a multipoint WKT fragment. * @param {String} str A WKT fragment representing the multipoint * @returns {OpenLayers.Feature.Vector} A multipoint feature * @private */ 'multipoint': function(str) { var point; var points = this.trim(str).split(','); var components = []; for(var i=0, len=points.length; i |
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