Fusion of high-resolution DEMs for water flow modeling

Anna Petrasova,Vaclav Petras,Helena Mitasova,Justyna Jeziorska

doi:10.1186/s40965-017-0019-2

Abstract

BackgroundNew technologies for terrain reconstruction have increased the availability of topographic data at a broad range of resolutions and spatial extents. The existing digital elevation models (DEMs) can now be updated at a low cost in selected study areas with newer, often higher resolution data using unmanned aerial systems (UAS) or terrestrial sensors. However, differences in spatial coverage and levels of detail often create discontinuities along the newly mapped area boundaries and subsequently lead to artifacts in results of DEM analyses or models of landscape processes.MethodsTo generate a seamless updated DEM, we propose a generalized approach to DEM fusion with a smooth transition while preserving important topographic features. The transition is controlled by distance-based weighted averaging along the DEMs’ blending overlap with spatially variable width based on elevation differences.ResultsWe demonstrate the method on two case studies exploring the effects of DEM fusion on water flow modeling in the context of precision agriculture. In the first case study, we update a lidar-based DEM with a fused set of two digital surface models (DSMs) derived from imagery acquired by UAS. In the second application, developed for a tangible geospatial interface, we fuse a georeferenced, physical sand model continuously scanned by a Kinect sensor with a lidar-based DEM of the surrounding watershed in order to computationally simulate and test methods for controlling storm water flow.ConclusionsThe results of our experiments demonstrate the importance of seamless, robust fusion for realistic simulation of water flow patterns using multiple high-resolution DEMs.

Highlights

New technologies for terrain reconstruction have increased the availability of topographic data at a broad range of resolutions and spatial extents
We demonstrate the proposed fusion method on two case studies located at the Lake Wheeler Road Field Laboratory of North Carolina (NC) State University in Raleigh, NC (Fig. 2)
Updating lidar-based digital elevation models (DEM) with unmanned aerial systems (UAS)-based digital surface model (DSM) The first case study provides an example of modeling water flow on very high-resolution DSM of a cultivated field, derived from imagery captured by a UAS and processed by Structure-from-Motion photogrammetry (SfM) technique

Summary

Introduction

New technologies for terrain reconstruction have increased the availability of topographic data at a broad range of resolutions and spatial extents. The different remote sensing sensors, platforms and DEM reconstruction algorithms result in DEM products with different properties in terms of spatial extent, resolution, accuracy, survey date, and. In these cases the fusion method combines several overlapping DEMs in order to obtain a higher quality DEM with homogenous error characteristics. As the errors are higher at the borders, decreased weights towards the borders allow for smoother transitions between DEMs. A different approach proposed by Reuter et al [10] creates seam lines along landscape features such as waterways or roads to merge nonoverlapping patches of DEMs with minimum geometric discontinuities. Depending on the complexity of landscape features the transition zone can be much smoother than its surrounding and become a visible artifact

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