坐标系7参转换 javascript.doc

最近要做坐标转换，采用arcgis server api for javascript，由于需要将一个局部坐标喜欢换为wgs84坐标系，所以geometry的project没办法解决问题。下面代码解决如何将一个局部坐标系转换为wgs84.转换之前要弄清这几个概念：大地坐标系（经纬度：BLH），平面直角坐标系（米：XYL），空间直角坐标系：（米：XYZ）。转换过程是：平面直角坐标系-大地坐标系-空间直角坐标系-7参转换-空间直角坐标系（目标）-大地坐标系-平面直角坐标系。/* * Created by xsg on 2014/6/23. */var pi_180 = Math.PI / 180;var _180_pi = 180 / Math.PI;var projectionTypes = ;projectionTypes.bj54 = a:6378245,/长半轴 e2:0.006693421622966/第一偏心率平方;projectionTypes.wgs84 = a:6378135,/长半轴 e2:0.00669437999013/第一偏心率平方;var myparams = dx : 31.4, dy : -144.3, dz : -74.8, rx : 0, ry : 0, rz : 0.814, m : -0.38;/7坐标系统转换方法/sourceType:源投影类型 targetType：目标投影类型 params： 7参数 blh：源大地坐标function coordinateTransfUse7params(sourceType,targetType,params,blh) sourceType = sourceType.toLowerCase(); targetType = targetType.toLowerCase(); var XYZ1 = _BLH2XYZ(sourceType,blh); var XYZ2 = _transXYZBy7params(XYZ1,params); var blh2 = _XYZ2BLH(targetType,XYZ2); console.log(blh2);function _BLH2XYZ(projectionType,blhObj)/将大地坐标喜欢换为空间直角坐标系 var e2 = projectionTypesprojectionType.e2;/第一偏心率平方值 var a = projectionTypesprojectionType.a;/长半轴 var N = a / Math.sqrt(1 - e2 * Math.sin(blhObj.b * pi_180) * Math.sin(blhObj.b * pi_180); var X = (N + blhObj.h) * Math.cos(blhObj.b * pi_180) * Math.cos(blhObj.l * pi_180); var Y = (N + blhObj.h) * Math.cos(blhObj.b * pi_180) * Math.sin(blhObj.l * pi_180); var Z = N * (1 - e2 ) + blhObj.h * Math.sin(blhObj.b * pi_180); var resultObj = ; resultObj.X = X; resultObj.Y = Y; resultObj.Z = Z; return resultObj;function _transXYZBy7params(xyz0,params)/根据7参数对空间直角坐标系进行运算 var x0 = xyz0.X; var y0 = xyz0.Y; var z0 = xyz0.Z; var dx = params.dx; var dy = params.dy; var dz = params.dz; var rx = params.rx; var ry = params.ry; var rz = params.rz; var m = params.m; var x1 = dx + (1 + m) * x0 + Math.sin(rz / 60 / 60 * pi_180) * y0 - Math.sin(ry / 60 / 60 * pi_180) * z0; var y1 = dy + (1 + m) * y0 - Math.sin(rz / 60 / 60 * pi_180) * x0 + Math.sin(rx / 60 / 60 * pi_180) * z0; var z1 = dz + (1 + m) * z0 + Math.sin(ry / 60 / 60 * pi_180) * x0 - Math.sin(rx / 60 / 60 * pi_180) * y0; var resultObj = ; resultObj.X = x1; resultObj.Y = y1; resultObj.Z = z1; return resultObj;function _XYZ2BLH(projectionType,xyz1) var a = projectionTypesprojectionType.a; var e2 = projectionTypesprojectionType.e2;/第一偏心率平方值 var X = xyz1.X; var Y = xyz1.Y; var Z = xyz1.Z; var L = Math.atan(Y / X) * _180_pi; var B = Math.atan(Z / Math.sqrt(X * X + Y * Y); while(true)/迭代计算 var N = a / Math.sqrt(1 - e2 * Math.sin(B) * Math.sin(B); var tempB = Math.atan(N * e2 * Math.sin(B) + Z ) / Math.sqrt(X * X + Y * Y ); B = Math.atan(Z + N * e2 * Math.sin(tempB) / Math.sqrt(X * X + Y * Y ); if(tempB = B) break; var H = Z / Math.sin(B) - N * (1 - e2); B = B * _180_pi; var resultObj = ; resultObj.L = L; resultObj.B