An Error Ellipse

Interaction and visualization of the standard error ellipses for survey engineers
(Created by Swatchai Kriengkraipet)

Input data

(Representing precision quantities)

σx (m):



σy (m):



ρxy:

The resulting covariance matrix of (x,y)
. .
. .

The standard error ellipse plot:
x y diagonal
Eigen values/vectors of covariance matrix
Eigen values Eigen vectors
λ1 v1
λ2 v2
Standard error ellipse's parameters
Semi major axis (a) sqrt(λ2)
Semi minor axis (b) sqrt(λ1)
Axis_a rotation from N eig_vector

©2021 Swatchai Kriengkraipet, Chulalongkorn University, Bangkok