An enhanced approach for surface flow routing over drainage‐constrained triangulated irregular networks

Abstract

The accuracy and efficiency of the simulations in distributed hydrological models must depend on the proper estimation of flow directions and paths. Numerous studies have been carried out to delineate the drainage patterns based on gridded digital elevation models (DEMs). The triangulated irregular network (TIN) has been increasingly applied in hydrological applications due to the advantages of high storage efficiency and multi-scale adaptive performance. Much of the previous literature focuses mainly on filling the depressions on gridded DEMs rather than treating the special cases in TIN structures, which has hampered its applications to hydrological models. This study proposes a triangulation-based solution for the removal of flat areas and pits to enhance the simulation of flow routing on triangulated facet networks. Based on the drainageconstrained TIN generated from only a gridded DEM by the compound point extraction (CPE) method, the inconsistent situations including flat triangles, V-shape flat edges and sink nodes are respectively identified and rectified. The optimization algorithm is an iterative process of TIN reconstruction, in which the flat areas are generalized into their center points and the pits are rectified by embedding break lines. To verify the proposed algorithm and investigate the potential for flow routing, flow paths of steepest descent are derived by the vector-based tracking algorithm based on the optimized TIN. A case study of TIN optimization and flow path tracking was performed on a real-world DEM. The outcomes indicate that the proposed approach can effectively solve the problem of inconsistencies without a significant loss in accuracy of the terrain model.

UAV-Based Biomass Estimation for Rice-Combining Spectral, TIN-Based Structural and Meteorological Features

“…TIN represents the surface with a series of continuous, non-overlapping, irregular triangles using the Delaunay triangulation algorithm. TIN has been used for studying the catchment hydrologic response [29], surface flow routing [30], and crown volume extraction [31]. Compared with gridded DEM, TIN is able to show surface structure details more accurately and more efficiently without the interpolation process [32,33].Temperature is one of the most important driving variables for the simulation of crop growth and development [34].…”

A Network‐Based Flow Accumulation Algorithm for Point Clouds: Facet‐Flow Networks (FFNs)

“…Conventionally, in gridded data sets, the issue of sinks is resolved either by filling up the depression or by carving a channel through the surrounding landscape, resulting in a modified, “hydrologically corrected” landscape (O'Callaghan & Mark, ; Planchon & Darboux, ; Rieger, ; Zhang et al, ). Other approaches avoid this modification by directing flow uphill out of a sink toward the outlet of that sink (Du et al, ; Wang et al, ).…”

“…A sink in digital topography is a single cell, or a group of grid cells that have no lower neighbor (Jenson & Domingue, ; O'Callaghan & Mark, ). Instead of carving or filling sinks in digital topography (e.g., O'Callaghan & Mark, ; Rieger, ; Planchon & Darboux, ; Soille et al, ; Zhang et al, ), we propose a fundamentally different approach that does not alter the digital topography. We introduce new additional links into the flow network that “tunnel” the flow out of sinks.…”

An Improved Algorithm for Simulating the Surface Flow Dynamics based on the Flow-Path Network Model

“…The keys to simulating the surface flow dynamics are effectively modelling the terrain surface, accurately calculating the flow velocity and quickly simulating the dynamic process. In terms of terrain surface modelling, the regular-grid digital elevation model (DEM) is widely utilized to describe terrain surfaces during the simulation of surface flow dynamics (Chen et al, 2014;Maneta and Wallender, 2013;Zhang et al, 2018;Zhou and Liu, 2006), such as the classical TOPMODEL (Beven and Kirkby, 1979) and Soil and Water Assessment Tool (SWAT) models (Arnold et al, 1998;Hellmers and Frohle, 2022). Although regular-grid DEMs can better describe continuous terrain surfaces, regular-grid DEMs have the same grid size, so it is difficult to fully and accurately express complex and changeable terrain surfaces, leading to the uncertainty of retrieving the critical points, lines and terrain parameters from regular-grid DEMs (David and Frank, 2013;Glenn and Ashton, 2012;Zhou and Liu, 2004).…”