Sensitivity of a physically based method for terrain interpolation to initial conditions and its conditioning on stream location

Production of digital elevation maps often requires interpolation of observations at particular locations. For hydrologic applications the resulting surface should have well defined drainage directions, should reproduce the roughness of natural terrain and should ideally preserve distributions of elevations, slopes and curvatures. The work of J. Niemann et al . (Water Resources Research, 2003, vol. 39, pp. 1017–1032) proposes a physically based interpolation method that is an improvement over commonly used linear or fractal interpolators. The methodology does have difficulty dealing with very sparse initial elevation and boundary flux information. This work suggests that using the commonly available horizontal location of main channels (‘blue lines’) improves the physical interpolation significantly. The results are illustrated on two river basins.