The United States Geological Survey has been researching generalization approaches to enable multiple-scale display and delivery of geographic data. This paper presents automated methods to prune network and polygon features of the United States high-resolution National Hydrography Dataset (NHD) to lower resolutions. Feature-pruning rules, data enrichment, and partitioning are derived from know...

This paper describes methods that use digital elevation models (DEMs) in hydrology, implemented as an ArcGIS toolbar using Visual Basic and the ESRI object library. I describe generalized channel network delineation to objectively estimate drainage density and by using terrain curvature accommodate spatially variable drainage density. The multiple flow direction field determined from a DEM also...

The flow directions of the extracted drainage network are more random based on random flow model. Binary linear regression method is applied to calculate the residual value at every point, and then the normalized residuals are used to prune reasonably as the variables. The terrains are distinguished automatically according to the normalized residuals, and the local catchment area threshold is d...

Introduction: Valley network systems on Mars remain the most unequivocal evidence that water carved the surface of the planet in the distant past and the climate was different than today. Most of these systems date from the Noachian [1], the p eriod of heavy bombardment which is >3.7 Ga [2], although local or regional formation seems to have continued to more recent times [3]. The discovery of ...

Although many sediment budgets estimate the effects of logging, few have considered the potential impact of timber harvesting on stream density. Failure to consider changes in stream density could lead to large errors in the sediment budget, particularly between the allocation of natural and anthropogenic sources of sediment. This study conducted field surveys in randomly selected catchments in...

development of pore network models for real porous media requires a detailed understanding of physical processes occurring on the microscopic scale and a complete description of porous media morphology. in this study, the microstructure of porous media has been represented by three dimensional networks of interconnected pores and throats which are designed by an object oriented approach. afterw...

sarygamesh basin one of the bulhary chay tributary take place in moghan plain, northeastern azarbyjan area in iran and south edge of kora- araz zone. aims of this research are study specificities and geomorphic evolution of sarygamesh basin, survey rivers work on structure and geologic formation, and corresponding hydrographic with earth structure. toward above aim is used to litologic, structu...

An analysis of channel head locations provides insight into controls on drainage density, the response of landscapes to climatic change, and the delineation of source areas for channel network simulations. Channel heads and colluvial deposits were mapped in a roughly 2 km 2 area near San Francisco, California, and, although channel heads are located within colluvial deposits in hollows, many su...