One of the most widely available procedures packaged with CIS for the analysis of a Digital Elevation Model (DEM) is the identification of the viewable area, or the viewshed. The elevations recorded in the DEM do, however, contain error, and the USGS, for example, publishes a Root Mean Squared Error (RMSE) for each DEM. Research reported here assesses the uncertainty of locations being within a...

Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Papers published in Hydrology and Earth System Sciences Discussions are under open-access review for the journal Hydrology and Earth System Sciences Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Abstract Digital elevation models (DEMs) represent the topography that drives s...

SUMMARY As part of ISO standards on public-key encryption, Shoup introduced the framework of KEM (Key Encapsulation Mechanism), and DEM (Data Encapsulation Mechanism), for formalizing and realizing one-directional hybrid encryption; KEM is a formalization of asymmetric en-cryption specified for key distribution, which DEM is a formalization of symmetric encryption. This paper investigates a mor...

A hydrologically correct digital elevation model (DEM) forms a basis for realistic environmental modelling, especially in complex terrain. We have performed a study in the Coarse Sandy Hilly Catchments (CSHC) of the Loess Plateau, China, which demonstrates pragmatic, yet effective methods for improving the quality of the DEM by: (1) identifying and correcting source topographic data errors and ...

This paper describes the effect of DEM data resolution on predictions from the SWAT model. Measured hydrologic, meteorological, watershed characteristics and water quality data from Moores Creek watershed (near Lincoln, AR, USA) were used in the simulation. The effect of input data resolution was evaluated by running seven scenarios at increasing DEM grid sizes (30 ð 30 m, 100 ð 100 m, 150 ð 15...

The existing grid-based DEM has several disadvantages in representing the features of real terrain surface, such as peak clipping, channel filling, etc. And abrupt changes in elevation cannot be handled easily and precisely. The inherent size of grid mesh affects the DEM computing, analysis and results. Through the discussion of DEM terrain distortion, the representative types of distortion wer...

The discrete element method (DEM) has been used as a popular simulation method in order to verify the designs by visualizing how materials flow through complex equipment geometries.  Although DEM simulation is a powerful design tool, finding a DEM model that includes all real material properties is not computationally feasible.  In order to obtain more realistic results, particle energy loss du...

Forest structure attributes produced from terrestrial laser scanning (TLS) rely on normalisation of the point cloud values from sensor coordinates to height above ground. One method to do this is through the derivation of an accurate and repeatable digital elevation model (DEM) from the TLS point cloud that is used to adjust the height. The primary aim of this paper was to test a number of TLS ...

Cave levels, passages found at similar elevations and formed during the same constant stream base level event, reveal information about paleoclimates and karst geomorphology. The investigation presented here examines how Stream Power Index (SPI) relates to cave levels. The study area, Carter Caves State Resort Park (CCSRP), is a fluviokarst system in northeastern Kentucky containing multiple ca...

Diagnostic electron microscopy (DEM) has conceptual predecessors â€" the application of the sense of vision and of light microscopy in medicine. The evolvement of DEM and the role of its two branches - histopathology and rapid negative-contrast DEM - are described in this review, with a focus on the latter. By its resolving power of 2 nm in praxi, DEM is able to visualize all kinds of pathogens...