Interpolate points that have a non-constant direction of anisotropy
The process for this method has been developed using a number of different open source software tools, including programming in python and spatial analysis in R, QGIS, and PostGIS. The goal of placing my code and desciption of the process on GitHub is to encourage help with turning this into a plugin for QGIS.
The original FOSS4G 2014 presentation describing the process can be found on [SlideShare] (http://www.slideshare.net/MicheleTobias/open-source-workflow-for-surface-interpolation-with-curvilinear-anisotropy).