Toward approximate moving least squares approximation with irregularly spaced centers

By combining the well-known moving least squares approximation method and the theory of approximate approximations due to Maz'ya and Schmidt we are able to present an approximate moving least squares method which inherits the simplicity of Shepard's method along with the accuracy of higher-order moving least squares approximations. In this paper we focus our interest on practical implementations for irregularly spaced data sites. The two schemes described here along with some first numerical experiments are to be viewed as exploratory work only. These schemes apply to centers that are obtained from gridded centers via a smooth parametrization. Further work to find a robust numerical scheme applicable to arbitrary scattered data is needed. (C) 2004 Elsevier B.V. All rights reserved.