The surveys are both 1cm Digital Earth Models (DEMs). However, computationally the grids are larger than can be handled in ArcMap, therefore the DEM was re-sampled to a resolution of 2cm so that hydrologic networks could be calculated. Mean absolute errors for x, y, and z in both surveys were less than or equal to +/- 3mm. The procedures for hydrologic flow network delineation are based on the Deterministic 8 (D8) model for flow over a 2cm DEM. The D8 method produces a single flow direction towards the steepest slope of one of eight grid cells neighboring the initial center cell (O’Callahan and Mark, 1984; Tarboton, 2003). The D8 method was chosen for its simplicity and widespread use in hydrologic terrain analysis (Kiss, 2004).
O'Callaghan, J. F. and D. M. Mark, (1984), "The Extraction of Drainage Networks from Digital Elevation Data," Computer Vision, Graphics and Image Processing, 28: 328-344.
Kiss, R.: Determination of drainage network in digital elevation model, utilities and limitations, Journal of Hungarian Geomathematics, 2, 16–29, 2004.
Tarboton, D.G. 2003 Terrain analysis using digital elevation models in hydrology, 23rd ESRI International Users Conference, San Diego, California.
This material is based upon work supported by the National Science Foundation (NSF) under Grant No. 0239749, entitled “CAREER: Alluvial Fan Form Quantification to Advance Geographic Science and Education” and Grant No. 0934131, entitled “Geomorphic Connectivity in a Recently Burned Watershed” - Thad Wasklewicz, PI
This material is also based upon work supported by a National Geographic Society CRE grant #8590-08 entitled “Rapid Assessment of Hydrological and Sedimentological Connectivity in a Recently Burned Watershed” - Thad Wasklewicz, PI