使用polyfit进行垂直线拟合 [英] Vertical line fit using polyfit

问题描述

这只是一个基本问题.我正在使用polyfit拟合线以分散点. 在某些情况下，我的散点具有相同的X值，并且polyfit无法对其拟合直线.必须有可以处理这种情况的东西.毕竟，这只是一条线.

Its just a basic question. I am fitting lines to scatter points using polyfit. I have some cases where my scatter points have same X values and polyfit cant fit a line to it. There has to be something that can handle this situation. After all, its just a line fit.

我可以尝试交换X和Y，然后换行.任何更简单的方法，因为我有很多分散点集，并希望使用通用方法来检查线.

I can try swapping X and Y and then fir a line. Any easier method because I have lots of sets of scatter points and want a general method to check lines.

主要目标是找到合适的线条并删除非线性特征.

Main goal is to find good-fit lines and drop non-linear features.

推荐答案

首先，这是由于您使用的拟合方法而发生的.进行polyfit时，您在距直线Y的距离上使用最小二乘法.

First of all, this happens due to the method of fitting that you are using. When doing polyfit, you are using the least-squares method on Y distance from the line.

_{(来源: une.edu.au )}

_{(source: une.edu.au)}

显然，它不适用于垂直线.顺便说一句，即使您有一些接近垂直线的地方，也可能会得到数值不稳定的结果.

Obviously, it will not work for vertical lines. By the way, even when you have something close to vertical lines, you might get numerically unstable results.

有2种解决方案:

1. 如您所说，交换x和y，如果您知道直线几乎是垂直的.然后，计算线性逆函数.
2. 在与直线垂直的距离上使用最小二乘，而不是垂直(请参见下图)(
   _{(摘自MathWorld-Wolfram网络资源:} wolfram.com )

   
   _{(from MathWorld - A Wolfram Web Resource: wolfram.com)}

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