Least Squares Fitting Method Based on Bivariate Nonuniform <i>B</i>-Spline and Its Applications in Surveying Engineering

Abstract

As a well-known numerical approximation method, the least squares fitting method is widely applied in surveying engineering. The most important and difficult problem in this method is to determine the type of base function to be used, and polynomial is the most frequently used type. But if the degree of polynomial is too high (⩾7), the normal equations are usually ill-conditioned. When we choose the uniform