TDataView_ui/scripts/meteo/other/smooth.js

/**
 * Created by Administrator on 2015/5/22.
 */
define([], function(){

	var xnew;
	var ynew;
	var sizenew;
	var addNewPointFlag;


	//线条平滑  ----二维数组
	function smoothLine(arrs,interval,distance){
		var points=getPositionFromDistance(arrs,distance);
		if(points) {
			var ps=points//getSmoothPositionFromAngle(points,0);
			var xs = [];
			var ys = [];
			for (var i = 0; i < ps.length; i++) {
				xs.push(parseFloat(ps[i][0]||ps[i].x));
				ys.push(parseFloat(ps[i][1]||ps[i].y));
			}
			return smooth(xs, ys, interval);
		}else{
			//console.log("没有平滑，抽取失败");
			return arrs;
		}
	}

	/**
	 * 间隔 样条平滑
	 * @param x 横坐标
	 * @param y 纵坐标
	 * @param interval 间隔
	 * @return 二维数组 第一纬为x 第二维为y
	 */
	function smooth( x,  y,interval) {
		var result = new Array(2);
		if (x == null || y == null || x.length != y.length) {
			result[0] = x;
			result[1] = y;
			return _formatPoint(result[0],result[1]);
		}
		var isClosed = false;
		if (x[0] == x[x.length - 1] && y[0] == y[y.length - 1]) {
			isClosed = true;
		}
		if (!isClosed) {
			var splineCount = getSplinePointCount(x, y, interval);
			result[0] = new Array(splineCount);
			result[1] = new Array(splineCount);
			splineProc(x, y, interval, result[0], result[1]);
			return _formatPoint(result[0],result[1]);
		}
		//处理闭合曲线 控制角度120
//		var angleBounder = 120;
//		var remark = 1;
//		for (remark = 1; remark < x.length - 1; remark++) {
//			if (getAngle(x[remark - 1] - x[remark], y[remark - 1] - y[remark],
//					x[remark + 1] - x[remark], y[remark + 1] - y[remark]) > angleBounder) {
//				break;
//			}
//		}
//		if (remark == x.length - 1) {
//			remark = 0;//不处理
//		}
//		var newX = shiftArray(x, remark);
//		var newY = shiftArray(y, remark);
		var splineCount = getSplinePointCount(x, y, interval);
		if(splineCount.length<= x.length){
			return _formatPoint(x,y);
		}

 		result[0] = new Array(splineCount);
		result[1] = new Array(splineCount);
		splineProc(x, y, interval, result[0], result[1]);
		return _formatPoint(result[0],result[1]);
	}
	/**
	 * 获取插值平滑后输出的点数
	 * @param x 横坐标
	 * @param y 纵坐标
	 * @param interval 间隔
	 * @return 个数
	 */
	function getSplinePointCount(x,  y, interval) {
		// 计算距离
		if (x.length != y.length) {
			////console.log("x长度：" + x.length + ", y长度：" + y.length);
			////console.log("In MIDS3DMath.getSplinePointCount()中输入的x y的长度不同");
		}
		if (x.length <= 2 || y.length <= 2) {
			////console.log("x、y的个数太少，无法插值");
			return x.length;
		}

		var size = x.length;
		var dis = new Array(size-1);
		var dmin = 0.0;
		var dmax = 0.0;

		// [-180,180]转换为[0,360]
		for (var i = 0; i < size; i++) {
			if (x[i] < -1e-10) {
				x[i] = x[i] + 360.0;
			}
		}
		for (var i = 0; i < size - 1; i++) {
			var tmp = (x[i + 1] - x[i]) * (x[i + 1] - x[i])
			+ (y[i + 1] - y[i]) * (y[i + 1] - y[i]);

			if (tmp != 0.0) {
				dmin = tmp;
				dmax = tmp;
				// break;
			}
		}

		if (dmin == 0.0 || dmax == 0.0) {
			//console.log("相邻两点间, 最小距离：" + dmin + "; 最大距离：" + dmax);
			//console.log("In MIDS3DMath.getSplinePointCount()中输入的点相同");
		}

		// 找到相邻两点之间的最大最小距离
		for (var i = 0; i < size - 1; i++) {
			dis[i] = (x[i + 1] - x[i]) * (x[i + 1] - x[i]) + (y[i + 1] - y[i])
			* (y[i + 1] - y[i]);

			if (dis[i] > dmax) {
				dmax = dis[i];
			}
			if (dis[i] < dmin && dis[i] != 0.0) {
				dmin = dis[i];
			}
		}

		var xinsert = [];
		var yinsert = [];

		addNewPointFlag = false;
		var MAXINTERVAL = 2000;// 两点之间最大最小距离>2000倍的时候不插值
		var MAXMINRATE = 6;// 两点之间最大最小距离小于6倍的不需要增加点，可直接进行插值
		var CURPTMINRATE = 4;// 当前点和最小距离之间的倍数小于4时，不增加点，4~8倍增加一个点，8~12倍增加两个点...
		for (var i = 0; i < size - 1; i++) {
			if (dmax < MAXMINRATE * MAXMINRATE * dmin) {
				break;
			}

			addNewPointFlag = true;
			xinsert.push(x[i]);
			yinsert.push(y[i]);

			var yytmp = y[i + 1] - y[i];
			var xxtmp = x[i + 1] - x[i];
			for (var j = 1; j < MAXINTERVAL / CURPTMINRATE; j++) {
				if (dis[i] <= CURPTMINRATE * CURPTMINRATE * dmin) {
					break;
				}

				if (dis[i] > j * j * CURPTMINRATE * CURPTMINRATE * dmin
					&& dis[i] <= (j + 1) * (j + 1) * CURPTMINRATE
					* CURPTMINRATE * dmin) {
					for (var k = 1; k <= j; k++) {
						var xtmp;
						var ytmp;
						if (yytmp == 0.0) {
							xtmp = x[i] + k * xxtmp / (j + 1);
							ytmp = y[i];
						} else {
							if (xxtmp == 0.0) {
								xtmp = x[i];
								ytmp = y[i] + k * yytmp / (j + 1);
							} else {
								xtmp = x[i] + k * xxtmp / (j + 1);
								ytmp = y[i] + k * yytmp / (j + 1);
							}
						}

						xinsert.push(xtmp);
						yinsert.push(ytmp);
					}
					break;
				}
			}
			if (dis[i] > MAXINTERVAL * MAXINTERVAL * dmin) {
				//console.log("x[" + i + "] = " + x[i] + ", y[" + i + "] = " + y[i]);
				//console.log("x[" + (i + 1) + "] = " + x[i + 1] + ", y[" + (i + 1) + "] = " + y[i + 1]);
				//console.log("以上两点之间的距离dis = " + dis[i]);
				//console.log("最小距离dmin = " + dmin);
				//console.log("In MIDS3DMath.getSplinePointCount()存在相邻两点之间的距离太大，插值不准确，请重新选择点");
				return 0;
				// throw new
				// RuntimeErrorException(null,"In MIDS3DMath.getSplinePointCount()存在相邻两点之间的距离太大，插值不准确，请重新选择点");
			}
		}// end for

		if (addNewPointFlag) {
			xinsert.push(x[size - 1]);
			yinsert.push(y[size - 1]);
		}
		if (xinsert.length!=0) {
			if (xinsert.length != yinsert.length) {
				//console.log("In MIDS3DMath.getSplinePointCount()增加的点的x y个数不同");
			}
		}

		if (xinsert.length==0) {
			sizenew = size;
			xnew = new Array(size);
			xnew = x;
			ynew = new Array(size);
			ynew = y;
		} else {
			sizenew = xinsert.length;
			xnew = new Array(sizenew);
			ynew = new Array(sizenew);
			for (var i = 0; i < sizenew; i++) {
				xnew[i] = xinsert[i];
				ynew[i] = yinsert[i];
			}
		}

		var xShift = new Array(sizenew);
		var yShift = new Array(sizenew);
		var t = new Array(sizenew);
		var index = [];
		for (var i = 0; i < sizenew; i++) {
			if (i == 0) {
				xShift[i] = xnew[sizenew - 1];
				yShift[i] = ynew[sizenew - 1];
			} else {
				xShift[i] = xnew[i - 1];
				yShift[i] = ynew[i - 1];
			}

			t[i] = Math.sqrt((xnew[i] - xShift[i])
			* (xnew[i] - xShift[i]) + (ynew[i] - yShift[i])
			* (ynew[i] - yShift[i]));
			if (i > 0 && t[i] > 0.0) {
				index.push(i);
			}
		}

		t[0] = 0.0;
		if (index.length==0) {
			return 0;
		}
		var length = index.length + 1;
		var xx = new Array(length);
		var yy = new Array(length);
		var tt = new Array(length);
		var r = 0;
		var rr = new Array(length);
		var kk = 0;
		for (var i = 0; i < length; i++) {
			if (i == 0) {
				xx[i] = xnew[0];
				yy[i] = ynew[0];
				tt[i] = t[0];
			} else {
				xx[i] = xnew[index[kk]];
				yy[i] = ynew[index[kk]];
				tt[i] = t[index[kk]];
				kk++;
			}
			rr[i] =  (Math.ceil(tt[i] / interval));
			r = parseInt(r + rr[i]);
		}

		return r + 1;
	}

	/**
	 * 线条平滑
	 * @param x 横坐标
	 * @param y 纵坐标
	 * @param interval 间隔
	 * @param xout 输出插值完成的横坐标
	 * @param yout 输出插值完成的纵坐标
	 * @return 插值平滑成功返回true，否则false
	 */
	function splineProc( x,  y,  interval,
		xout, yout) {
		if (xout.length == 0 || yout.length == 0) {
			return [x,y];
		}
		if (x == null || y == null) {
			//console.log("x或y为null");
			return [x,y];
		}
		if (x.length != y.length) {
			////console.log("x长度：" + x.length + ", y长度：" + y.length);
			////console.log("In MIDS3DMath.getSplinePointCount()中输入的x y的长度不同");
		}
		if (x.length <= 2 || y.length <= 2) {
			////console.log("x、y的个数太少，无法插值");
			xout = x;
			yout = y;
			return [x,y];
		}

		// [-180,180]转换为[0,360]
		for (var i = 0; i < x.length; i++) {
			if (x[i] < 1e-10) {
				x[i] = x[i] + 360.0;
			}
		}

		if (!addNewPointFlag) {
			var xSize = x.length;
			var ySize = y.length;
			if (xSize != ySize) {
				//console.log("In MIDS3DMath.splineProcAry()中输入的x,y点的个数不同");
				return false;
			}
			if (xSize <= 2) {
				//console.log("In MIDSMath.splineProcAry()中x,y的个数太少,不满足平滑条件,按原值返回");
				xout = x;
				yout = y;
				return true;
			}
			var size = xSize;
			var xShift = new Array(size);
			var yShift = new Array(size);
			var t = new Array(size);
			var index = [];

			for (var i = 0; i < x.length; i++) {
				if (i == 0) {
					xShift[i] = x[size - 1];
					yShift[i] = y[size - 1];
				} else {
					xShift[i] = x[i - 1];
					yShift[i] = y[i - 1];
				}

				t[i] = Math.sqrt((x[i] - xShift[i])
				* (x[i] - xShift[i]) + (y[i] - yShift[i])
				* (y[i] - yShift[i]));
				if (i > 0 && t[i] > 0.0) {
					index.push(i);
				}
			}

			t[0] = 0.0;
			if (index.length==0 || index.length < 2) {
				return false;
			}
			var length = index.length + 1;
			var xx = new Array(length);
			var yy = new Array(length);
			var tt = new Array(length);
			var r = 0;
			var rr = new Array(length);
			var kk = 0;
			for (var i = 0; i < length; i++) {
				if (i == 0) {
					xx[i] = x[0];
					yy[i] = y[0];
					tt[i] = t[0];
				} else {
					xx[i] = x[index[kk]];
					yy[i] = y[index[kk]];
					tt[i] = t[index[kk]];
					kk++;
				}
				rr[i] = Math.ceil(tt[i] / interval);
				r = parseInt(r + rr[i]);
			}

			var count = r + 1;
			if (xout.length < count){
				return false;
			}
			var ttt = new Array(count);
			var k;
			var j = 0;
			for (var i = 1; i < length; i++) {
				k = parseInt(rr[i]);
				for (var m = 0; m < k; m++) {
					ttt[parseInt(j + m)] = m * (tt[i] / k) + tt[i - 1];
				}
				tt[i] = tt[i] + tt[i - 1];
				j = j + k;
			}
			ttt[parseInt(j)] = tt[length - 1];
			var xp = new Array(count);
			var yp = new Array(count);
			xp = spline(tt, xx, ttt);
			yp = spline(tt, yy, ttt);
//			if (xout.length < count){
//				System.err.println("In MIDS3DMath splineProc...中 平滑后的元素xout的长度小于原始数据的长度!该线条进行样条平滑失败!");
//				return false;
//			}

			for (var i = 0; i < count; i++) {
				if (xp[i] - 180.0 > 1e-10) {
					xout[i] = xp[i] - 360.0;
				} else {
					xout[i] = xp[i];
				}
				yout[i] = yp[i];
			}

			if (xout.length != yout.length) {
				//console.log("In MIDS3DMath.splineProc()中平滑插值出的x,y值个数不同,出错");
				return false;
			}
			//如果是闭合线则必须保证首尾两点相等
			if(x[0]==x[x.length-1] && y[0]==y[y.length-1]){
				if(xout[0]!=xout[count-1]){
					xout[count-1]=xout[0];
				}
				if(yout[0]!=yout[count-1]){
					yout[count-1]=yout[0];
				}
			}
			xp = null;
			yp = null;
			return true;
		} else {
			var xSize = xnew.length;
			var ySize = ynew.length;
			if (xSize != ySize) {
				//console.log("In MIDS3DMath.splineProcAry()中输入的x,y点的个数不同");
				return false;
			}
			if (xSize <= 2) {
				//console.log("In MIDSMath.splineProcAry()中x,y的个数太少,不满足平滑条件,按原值返回");
				xout = xnew;
				yout = ynew;
				return true;
			}
			var size = xSize;
			var xShift = new Array(size);
			var yShift = new Array(size);
			var t = new Array(size);
			var index = [];
			for (var i = 0; i < size; i++) {
				if (i == 0) {
					xShift[i] = xnew[size - 1];
					yShift[i] = ynew[size - 1];
				} else {
					xShift[i] = xnew[i - 1];
					yShift[i] = ynew[i - 1];
				}

				t[i] =  Math.sqrt((xnew[i] - xShift[i])
				* (xnew[i] - xShift[i]) + (ynew[i] - yShift[i])
				* (ynew[i] - yShift[i]));
				if (i > 0 && t[i] > 0.0) {
					index.push(i);
				}
			}

			t[0] = 0.0;
			if (index.length==0) {
				return false;
			}
			var length = index.length + 1;
			var xx = new Array(length);
			var yy = new Array(length);
			var tt = new Array(length);
			var r = 0;
			var rr = new Array(length);
			var kk = 0;
			for (var i = 0; i < length; i++) {
				if (i == 0) {
					xx[i] = xnew[0];
					yy[i] = ynew[0];
					tt[i] = t[0];
				} else {
					xx[i] = xnew[index[kk]];
					yy[i] = ynew[index[kk]];
					tt[i] = t[index[kk]];
					kk++;
				}
				rr[i] = Math.ceil(tt[i] / interval);
				r = parseInt(r + rr[i]);
			}

			var count = r + 1;
			var ttt = new Array(count);
			var k;
			var j = 0;
			for (var i = 1; i < length; i++) {
				k = parseInt(rr[i]);
				for (var m = 0; m < k; m++) {
					ttt[parseInt(j + m)] = m * (tt[i] / k) + tt[i - 1];
				}
				tt[i] = tt[i] + tt[i - 1];
				j = j + k;
			}

			ttt[parseInt(j)] = tt[length - 1];
			var xp = new Array(count);
			var yp = new Array(count);
			xp = spline(tt, xx, ttt);
			yp = spline(tt, yy, ttt);
			for (var i = 0; i < count; i++) {
				if (xp[i] - 180.0 > 1e-10) {
					xout[i] = xp[i] - 360.0;
				} else {
					xout[i] = xp[i];
				}
				yout[i] = yp[i];
			}

			if (xout.length != yout.length) {
				//console.log("In MIDS3DMath.splineProc()中平滑插值出的x,y值个数不同,出错");
				return false;
			}
			//如果是闭合线则必须保证首尾两点相等
			if(x[0]==x[x.length-1] && y[0]==y[y.length-1]){
				if(xout[0]!=xout[count-1]){
					xout[count-1]=xout[0];
				}
				if(yout[0]!=yout[count-1]){
					yout[count-1]=yout[0];
				}
			}
			xp = null;
			yp = null;
			return true;
		}
	}
	/**
	 * @param x
	 * @param y
	 * @param t
	 * @return
	 */
	function spline( x, y, t) {
		var xLen = x.length;
		var yLen = y.length;
		var tLen = t.length;
		if (xLen != yLen) {
			//console.log("In MIDS3DMath.spline()中 X and Y must have same elements.");
			return null;
		}
		if (xLen <= 2) {
			//console.log("In MIDS3DMath.spline()中 X and Y must be arrays of 3 or more elements.");
			return null;
		}
		var size = xLen;
		var sigma = 1.0;
		var yp = new Array(2 * size);

		var delx1 = x[1] - x[0];
		var dx1 = (y[1] - y[0]) / delx1;
		var delx2 = x[2] - x[1];
		var delx12 = x[2] - x[0];
		var c1 = -(delx12 + delx1) / delx12 / delx1;
		var c2 = delx12 / delx1 / delx2;
		var c3 = -delx1 / delx12 / delx2;

		var slpp1 = c1 * y[0] + c2 * y[1] + c3 * y[2];
		var nm1 = size - 1;
		// var np1 = size + 1;
		var deln = x[nm1] - x[nm1 - 1];
		var delnm1 = x[nm1 - 1] - x[nm1 - 2];
		var delnn = x[nm1] - x[nm1 - 2];
		c1 = (delnn + deln) / delnn / deln;
		c2 = -delnn / deln / delnm1;
		c3 = deln / delnn / delnm1;
		var slppn = c3 * y[nm1 - 2] + c2 * y[nm1 - 1] + c1 * y[nm1];

		var sigmap = sigma * nm1 / (x[nm1] - x[0]);
		var dels = sigmap * delx1;
		var exps =  Math.exp(dels);
		var sinhs = 0.5 * (exps - 1.0 / exps);
		var sinhin = 1.0 / (delx1 * sinhs);
		var diag1 = sinhin * (dels * 0.5 * (exps + 1.0 / exps) - sinhs);
		var diagin = 1.0 / diag1;
		yp[0] = diagin * (dx1 - slpp1);
		var spdiag = sinhin * (sinhs - dels);
		yp[size] = diagin * spdiag;

		var delxx2 = new Array(size-1);
		var delss = new Array(size-1);
		var dx2 = new Array(size-1);
		var expss = new Array(size-1);
		var sinhss = new Array(size-1);
		var sinhnn = new Array(size-1);
		var diag2 = new Array(size-1);
		var spdiagg = new Array(size-1);

		for (var i = 0; i < size - 1; i++) {
			delxx2[i] = x[i + 1] - x[i];
			dx2[i] = (y[i + 1] - y[i]) / delxx2[i];
			delss[i] = sigmap * delxx2[i];
			expss[i] =  Math.exp(delss[i]);
			sinhss[i] = 0.5 * (expss[i] - 1.0 / expss[i]);
			sinhnn[i] = 1.0 / (delxx2[i] * sinhss[i]);
			diag2[i] = sinhnn[i]
			* (delss[i] * (0.5 * (expss[i] + 1.0/ expss[i])) - sinhss[i]);
			spdiagg[i] = sinhnn[i] * (sinhss[i] - delss[i]);
		}
		var dx2nm1 = dx2[nm1 - 1];
		var tmpdiag2 = new Array(size - 2);
		var tmpdx2 = new Array(size - 2);
		for (var i = size - 1 - 1 - 1; i >= 0; i--) {
			tmpdiag2[i] = diag2[i + 1];
			diag2[i + 1] = diag2[i] + tmpdiag2[i];
			tmpdx2[i] = dx2[i + 1];
			dx2[i + 1] = tmpdx2[i] - dx2[i];
		}
		diag2[0] = 0;
		dx2[0] = 0;
		for (var i = 1; i <= nm1 - 1; i++) {
			diagin = 1.0 / (diag2[i] - spdiagg[i - 1] * yp[i + size - 1]);
			yp[i] =  diagin * (dx2[i] - spdiagg[i - 1] * yp[i - 1]);
			yp[i + size] =diagin * spdiagg[i];
		}
		diagin = 1.0 / (diag1 - spdiagg[nm1 - 1] * yp[size + nm1 - 1]);
		yp[nm1] = diagin * (slppn - dx2nm1 - spdiagg[nm1 - 1]
		* yp[nm1 - 1]);
		for (var i = size - 2; i >= 0; i--) {
			yp[i] = yp[i] - yp[i + size] * yp[i + 1];

		}
		var subs = new Array(tLen);
		for (var i = 0; i < tLen; i++) {
			subs[i] = nm1;
		}
		var s = x[nm1] - x[0];
		sigmap = sigma * nm1 / s;
		var j = 0;
		for (var i = 1; i <= nm1; i++) {
			while (t[j] < x[i]) {
				subs[j] = i;
				j++;
				if (j == tLen) {
					return getSplineData(tLen, subs, sigmap, x, y, t, yp);
				}
			}
		}
		return getSplineData(tLen, subs, sigmap, x, y, t, yp);
	}
	/**
	 *
	 * @param tLen
	 * @param subs
	 * @param sigmap
	 * @param x
	 * @param y
	 * @param t
	 * @param yp
	 * @return
	 */
	function getSplineData( tLen,  subs, sigmap,
		 x, y,  t,  yp) {
		/*var subs1 = new Array(tLen];
		var del1 = new Array(tLen];
		var del2 = new Array(tLen];
		var delss1 = new Array(tLen];
		var exps1 = new Array(tLen];
		var exps2 = new Array(tLen];
		var exps3 = new Array(tLen];
		var sinhd1 = new Array(tLen];
		var sinhd2 = new Array(tLen];
		var sinhs2 = new Array(tLen];
		var spl = new Array(tLen];

		for (var k = 0; k < tLen; k++) {
			subs1[k] = subs[k] - 1;
			del1[k] = t[k] - x[subs1[k]];
			del2[k] = x[subs[k]] - t[k];
			delss1[k] = x[subs[k]] - x[subs1[k]];
			exps1[k] = (var) Math.exp(sigmap * del1[k]);
			sinhd1[k] = 0.5f * (exps1[k] - 1.0f / exps1[k]);
			exps2[k] = (var) Math.exp(sigmap * del2[k]);
			sinhd2[k] = 0.5f * (exps2[k] - 1.0f / exps2[k]);
			exps3[k] = exps1[k] * exps2[k];
			sinhs2[k] = 0.5f * (exps3[k] - 1.0f / exps3[k]);
			spl[k] = (yp[subs[k]] * sinhd1[k] + yp[subs1[k]] * sinhd2[k]) / sinhs2[k]
			+ ((y[subs[k]] - yp[subs[k]]) * del1[k] + (y[subs1[k]] - yp[subs1[k]]) * del2[k]) / delss1[k];
		}

		var spl2 = new var { spl[0] };
		return (tLen == 1) ? spl2 : spl;*/
		var subs1 = new Array(tLen);
		var del1 = new Array(tLen);
		var del2 = new Array(tLen);
		var delss1 = new Array(tLen);
		var exps1 = new Array(tLen);
		var exps2 = new Array(tLen);
		var exps3 = new Array(tLen);
		var sinhd1 = new Array(tLen);
		var sinhd2 = new Array(tLen);
		var sinhs2 = new Array(tLen);
		var spl = new Array(tLen);
		for (var k = 0; k < tLen; k++) {
			subs1[k] = subs[k] - 1;
			del1[k] = t[k] - x[subs1[k]];
			del2[k] = x[subs[k]] - t[k];
			delss1[k] = x[subs[k]] - x[subs1[k]];
			exps1[k] = Math.exp(sigmap * del1[k]);
			sinhd1[k] = 0.5 * (exps1[k] - 1 / exps1[k]);
			exps2[k] = Math.exp(sigmap * del2[k]);
			sinhd2[k] = 0.5 * (exps2[k] - 1 / exps2[k]);
			exps3[k] = exps1[k] * exps2[k];
			sinhs2[k] = 0.5 * (exps3[k] - 1 / exps3[k]);
			spl[k] = (yp[subs[k]] * sinhd1[k] + yp[subs1[k]] * sinhd2[k]) / sinhs2[k]
			+ ((y[subs[k]] - yp[subs[k]]) * del1[k] + (y[subs1[k]] - yp[subs1[k]]) * del2[k]) / delss1[k];
		}
		return (tLen == 1) ? [spl[0]] : spl;
	}



	/**
	 * 对一列有序的点根据距离间隔distance抽取大于此距离的点
	 * @param linePos 有序点集合
	 * @param distance 距离条件
	 * @return 大于distance的点集
	 */
	function getPositionFromDistance( linePos, distance) {
		if (linePos == null || linePos.length==0) {
			return null;
		}
		// System.out.println("原始点个数：" + linePos.size());
		var newPos = [];
		for(var i in linePos){
			newPos[i]=linePos[i];
		}

		var  size = newPos.length;
		var flag = newPos[0]==newPos[size - 1];// 第一个点和最后一个点是否重合，即这些点构成的多边形是否闭合

		var dist;
		var j = 0;
		var hasMinDistPtflag = true;
		while (hasMinDistPtflag) {
			var hasFlag = false;
			for (var i = 0; i < newPos.length - 1; i++) {
				if(newPos[i]) {
					j = i + 1;
					while (!newPos[j] && j < newPos.length){
						j ++;
					}
					if(j==newPos.length){
						break;
					}
					// 判断距离，去除距离很近的后一个点
					dist = getDistanceFrom2Pts(newPos[i], newPos[j]);
					if (dist < distance) {
						if (j == newPos.length - 1) {
							delete newPos[i];// 不能去除最后一个点
						} else {
							delete newPos[j]
						}
						hasMinDistPtflag = true;
						hasFlag = true;
						break;
					}
				}
			}
			if (!hasFlag) {
				hasMinDistPtflag = false;
			}
		}
		if (flag) {
			if (newPos.length < 4) {
				return null;
			}
		} else {
			if (newPos.length < 2) {
				return null;
			}
		}
		var arr=[];
		for(var i in newPos){
			arr.push(newPos[i]);
		}

		return arr;
	}




	/**
	 * 对一列有序的点根据角度maxAngle去毛刺，尖角，
	 * @param linePos 有序点集合
	 * @param maxAngle 角度条件
	 * @return 平滑去毛刺后的点集
	 */
	function  getSmoothPositionFromAngle(  linePos,  maxAngle) {
		if (linePos == null || linePos.length==0) {
			//console.log("原始点个数：" + linePos.size());
			return null;
		}
		// System.out.println("原始点个数：" + linePos.size());
		var newPos = [];
		for(var i in linePos){
			newPos[i]=linePos[i];
		}

		var size = newPos.length;
		if (size <= 10) {
			return newPos;// 暂定小于等于10个点返回；点太少，处理后形状会改变太大
		}

		// boolean flag =
		// newPos.get(0).equals(newPos.get(size-1));//第一个点和最后一个点是否重合，即这些点构成的多边形是否闭合
		var inclination;// 夹角
		var j = 0;
		var k = 0;
		var hasMinAnglePtFlag = true;
		while (hasMinAnglePtFlag) {
			var hasFlag = false;
			for (var i = 1; i < newPos.length - 1; i++) {
				if(newPos[i]) {
					j = i - 1;
					while(!newPos[j]&&j>=0){
						j--;
					}
					k = i + 1;
					while(!newPos[k]&&k<newPos.length){
						k++
					}
					if(j<0||k==newPos.length){
						break;
					}
					// 根据角度条件去除毛刺
					inclination = getAngleFrom3Pts(newPos[j], newPos[i], newPos[k]);
					if (inclination < maxAngle) {
						delete newPos[i];
						hasMinAnglePtFlag = true;
						hasFlag = true;
						break;
					}
				}
			}
			if (!hasFlag) {
				hasMinAnglePtFlag = false;
			}

			if (newPos.length <= 4) {// 小于四个点直接返回；如果小于4个点还去毛刺，有可能会导致只剩一个点
				//console.log("点数小于4个");
				break;
			}
		}

		var arr=[];
		for(var i in newPos){
			arr.push(newPos[i]);
		}

		return arr;
	}

	/**
	 * 算两个点之间的距离
	 * @param pt1
	 * @param pt2
	 * @returns {*}
	 */
	function getDistanceFrom2Pts(p1,p2){
		if(p1&&p2) {
			return Math.sqrt((p1[0] - p2[0]) * (p1[0] - p2[0]) + (p1[1] - p2[1]) * (p1[1] - p2[1]));
		}else{
			//console.log("点数据错误");
			return 2000;
		}
	}


	/**
	 * 三点之间的夹角
	 * @param p1
	 * @param p2 夹角所在点
	 * @param p3
	 * @return
	 */
	function getAngleFrom3Pts( p1,  p2,  p3) {
		var a2 = (p1[0] - p2[0]) * (p1[0] - p2[0]) + (p1[1] - p2[1]) * (p1[1] - p2[1]);
		var c2 = (p1[0] - p3[0]) * (p1[0] - p3[0]) + (p1[1] - p3[1]) * (p1[1] - p3[1]);
		var b2 = (p2[0] - p3[0]) * (p2[0] - p3[0]) + (p2[1] - p3[1]) * (p2[1] - p3[1]);
		var a = Math.sqrt(a2);
		var b = Math.sqrt(b2);
		var tmp2ab = 2 * a * b;
		var cosC = (a2 + b2 - c2) / tmp2ab;
		if(cosC>0.999){
			cosC=0.999;
		}else if(cosC<-0.999){
			cosC=-0.999;
		}
		return  Math.acos(cosC)/Math.PI*180;

	}



	/**
	 * 将结果重新组织成二维数组
	 * @param arr1
	 * @param arr2
	 * @returns {Array}
	 * @private
	 */
	function _formatPoint(arr1,arr2){
		var result=[];
		for(var i=0;i<arr1.length;i++){
			if(arr1[i]&&arr2[i])
			result.push([arr1[i],arr2[i]]);
		}
		return result;
	}

	return smoothLine;

});