River network completion without height samples using geometry-based induced terrain

This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. We present an improved method for connecting broken river segments by incorporating segment geometry into the induced terrain approach. The reconnection problem is important in aerial photography. Canopies and clouds cover parts of rivers, and a complete river network is necessary for transportation, land-use planning, and floodplain control. Our previously presented induced terrain approach guarantees that the global network topology is hydrologically consistent. However, it assumes many reliable height samples, which may be unavailable because of extensive view obstacles or gentle surfaces, to reconstruct the induced terrain surface. In this paper, we exploit river segment geometries to generate the induced terrain. We assign lowest heights to the known river locations, and higher and higher heights for locations further and further away. Since areas radiating from segment tips tend to be where a river is broken, we assign relatively small heights to these areas, so as to favor water flow toward them in the subsequent river derivation. On average, such a tip-biased model improves reconnection accuracy by five percentage points (which is 40% of what we would have been corrected if we had had rich height samples covering 10% of the terrain cells) over the intuitive baseline model in which the height of a location increases with its distance from the respective nearest river location, without considering the potential effect of segment tips as the tip-biased approach. 1. Introduction This paper presents how river segment geometry can be combined with the induced terrain approach (Lau and Franklin 2011) to improve river segment reconnection when rich terrain height samples are unavailable. The river network completion problem is important since many transportation issues, such as ship routing, pollutant monitoring, and floodplain control, rely on full network information. Due to their capability …