Title of Manuscript: An Efficient Assignment of Drainage Direction Over Flat Surfaces in Raster Digital Elevation Models
Authors: Richard Barnes, Clarence Lehman, David Mulla
Corresponding Author: Richard Barnes (rbarnes@umn.edu)
DOI Number of Manuscript 10.1016/j.cageo.2013.01.009
Code Repositories
This repository contains a reference implementation of the algorithms presented in the manuscript above. It also contains a reference implementation of the algorithm presented by Garbrecht and Martz (1997). These implementations were used in performing speed comparison tests in the manuscript.
All the programs can be produced simply by running make.
The program generate_square_grid.exe makes a square DEM with a single outlet near the bottom-left corner. The grid size is specified as a command-line argument.
The two reference implementations use the D8 neighbour system to indicate flow directions. In this system all the flow from a central cell is directed to a single neighbour which is represented by a number according to the following system where 0 indicates the central cell.
234
105
876
The program barnes_algorithm.exe reads in a DEM file specified on the command line. The file may be generated by generate_square_grid.exe, but may also be any ArcGrid ASCII file. The program will time itself and report the results back. The program will print the determined flow directions for the DEM to a file named out_barnes. The determined flow directions are also printed as a matrix of arrows to out_barnes_arrows.
The program garbrecht_algorithm.exe attempts to reproduce the algorithm described by Garbrecht and Martz (1997). It accepts an ArcGRID ASCII file as a command line input. The input file may also be generated with generate_square_grid.exe. Note that this implementation does not apply itself iteratively, meaning that some flats will be unresolvable. It writes the determined flow directions to out_garbrecht. The determined flow directions are also printed as a matrix of arrows to out_garbrecht_arrows.
The directory src/ contains the source code for reference implementations. The source for the improved algorithm is drawn from the RichDEM hydroanalysis package. All code can be compiled by running the makefile included in the root directory. Running the BASH script FIRST_RUN will compile everything and run the programs.
At the time of writing, the entire RichDEM code base could be downloaded from: https://github.com/r-barnes