LeastSquares Circle Calculator
What is LeastSquares Circle Calculator
A leastsquares circle calculator is a tool used to find the bestfitting circle to a set of data points by minimizing the sum of squared distances between the data points and the circle. It calculates the parameters of the circle, such as the center coordinates and radius, based on the method of least squares.
The leastsquares circle fitting algorithm aims to find the circle that minimizes the sum of the squared differences between the observed data points and the corresponding points on the circle. This approach is commonly used when there is noise or uncertainty in the data.
Here's how you can use a leastsquares circle calculator:

Input your data: You need a set of 2D data points (x, y) representing the coordinates of the points in the plane.

Perform the calculation: The leastsquares circle calculator will determine the bestfitting circle by estimating its parameters, including the xcoordinate of the center (h), the ycoordinate of the center (k), and the radius (r).

Interpret the results: The center coordinates (h, k) represent the location of the circle's center, and the radius (r) specifies the distance from the center to any point along the circle.

Visualize the circle: The calculator may provide a graphical representation of the data points and the fitted circle to help visualize the relationship.
Please note that the leastsquares circle fitting algorithm assumes that the data points are distributed uniformly around the circle and that the noise or errors in the measurements are normally distributed.
If you provide me with the specific data points or any additional information, I can assist you further by performing a leastsquares circle fitting analysis.
Understanding the Best Fit Circle
In a situation in which you have the data points x, y that are distributed in a ringshape on an xy plane, the leastsquares regression can be used to determine the equation of a circle that will best fit with the available data points; i.e., the following regression will help you to calculate the k, m, and r values of the curve:
(x âˆ’ k)^{2} + (y âˆ’ m)^{2} = r^{2}
When you use the leastsquares, you determine the "best fit" by minimizing the equation as follows:
F(k, m, r) = âˆ‘[(x_{i} âˆ’ k)^{2} + (y_{i} âˆ’ m)^{2} âˆ’ r^{2}]^{2}
The equation of the circle is linearized by the model âˆ‚F/âˆ‚k = 0, âˆ‚F/âˆ‚m = 0, and âˆ‚F/âˆ‚r = 0. As such, we have the following:
(x âˆ’ k)^{2} + (y âˆ’ m)^{2} = r^{2}
x^{2} âˆ’ 2kx + k^{2} + y^{2} âˆ’ 2my + m^{2} = r^{2}
x^{2} + y^{2} = 2kx + 2my + r^{2} âˆ’ k^{2} âˆ’ m^{2}
x^{2} + y^{2} = Ax + By + C
This results in a linear equation with the coefficients A, B, and C undetermined. As such, you can use the matrices to solve the leastsquares problem. Once you have determined A, B, and C, it is possible to work backward to compute k, m, and r.
Finding A, B, and C with Matrices
The circle regression model is supported by the following matrix equation:
where n is the number of data points (x_{i}, y_{i}).
In a situation in which the 3by3 matrix outlined on the left is invertible, the A, B, and C values are unique, and this determines the best fit circle.
You can use the A, B, and C values to subsequently determine k, m, and r:
k = A/2
m = B/2
r = (âˆš4C + AÂ² + BÂ²)/2
Example:
Let's say we want to identify the equation of the circle that best fits the following four data points: (0, 1), (2, 5), (1, 6), and (7, 6).
The use of the matrix equation or the least squares circle calculator results in the following:
(x âˆ’ 4.2408)^{2} + (y âˆ’ 2.4630)^{2} = 4.3220^{2}.
LeastSquares Circle Calculator Example
Certainly! The leastsquares circle fitting method can be used to find the bestfitting circle for a given set of data points. Here's an example of how you can calculate the leastsquares circle using a simple dataset:
Let's say we have the following dataset:
X = [1, 2, 3, 4, 5] # xcoordinates of data points Y = [2, 4, 6, 8, 10] # ycoordinates of data points
To calculate the leastsquares circle, we need to find the center coordinates (a, b) and radius r of the circle that minimizes the sum of squared differences between the actual data points and the predicted points on the circle.
In this example, we can calculate the leastsquares circle with the following steps:
Step 1: Calculate the mean of X and Y.
 Mean(X) = (1 + 2 + 3 + 4 + 5) / 5 = 3
 Mean(Y) = (2 + 4 + 6 + 8 + 10) / 5 = 6
Step 2: Calculate the deviations from the mean for X and Y.
 Deviations(X) = [1  3, 2  3, 3  3, 4  3, 5  3] = [2, 1, 0, 1, 2]
 Deviations(Y) = [2  6, 4  6, 6  6, 8  6, 10  6] = [4, 2, 0, 2, 4]
Step 3: Calculate the squared deviations for X and Y.
 Squared(Deviations(X)) = [(2)^2, (1)^2, 0^2, 1^2, 2^2] = [4, 1, 0, 1, 4]
 Squared(Deviations(Y)) = [(4)^2, (2)^2, 0^2, 2^2, 4^2] = [16, 4, 0, 4, 16]
Step 4: Calculate the sum of squared deviations for X and Y.
 Sum(Squared(Deviations(X))) = 4 + 1 + 0 + 1 + 4 = 10
 Sum(Squared(Deviations(Y))) = 16 + 4 + 0 + 4 + 16 = 40
Step 5: Calculate the sum of the product of X and Y deviations.
 Sum(Product(Deviations(X) * Deviations(Y))) = (2 * 4) + (1 * 2) + (0 * 0) + (1 * 2) + (2 * 4) = 8 + 2 + 0 + 2 + 8 = 20
Step 6: Calculate the intermediate variables A, B, and C.
 A = (Sum(Squared(Deviations(X))) + Sum(Squared(Deviations(Y)))) / N = (10 + 40) / 5 = 50 / 5 = 10
 B = (2 * Sum(Product(Deviations(X) * Deviations(Y)))) / N = (2 * 20) / 5 = 40 / 5 = 8
 C = Mean(Squared(Deviations(X))) + Mean(Squared(Deviations(Y))) = (10 / 5) + (40 / 5) = 2 + 8 = 10
Step 7: Calculate the circle center coordinates (a, b).
 a = B / (2 * C) = 8 / (2 * 10) = 0.4
 b = Mean(Y)  (a * Mean(X)) = 6  (0.4 * 3) = 4.8
Step 8: Calculate the radius r of the circle.
 r = sqrt(A + a^2 + b^2) = sqrt(10 + 0.4^2 + 4.8^2) â‰ˆ sqrt(10 + 0.16 + 23.04) â‰ˆ sqrt(33.2) â‰ˆ 5.76
Therefore, the bestfitting circle for the given dataset has a center at (0.4, 4.8) and a radius of approximately 5.76.