Traditional approaches to interpolating a surface from point samples often assume that if anisotropy is present in the data, it is along a straight line. However, this assumption breaks down for many data-sets, such as river bathymetry, elevations near coastlines, or levels of pollutants along roads. I will present a work-flow using open source tools to make use of the curvilinear anisotropy present in many data-sets by transforming the curved data-set into a straight line (QGIS and PostGIS), applying an interpolation to the transformed data (SAGA, GRASS, or other program with interpolation tools), and finally re-bending the interpolated surface back to the data's original shape (PostGIS).
