We study the practical aspects of performing terrain corrections in airborne/seaborne gravity gradient surveys in terms of necessary spatial extents and required resolution of digital elevation models. We develop a new and practical method for performing terrain corrections through an extension of Parker’s 1972 method for calculating potential anomalies in the Fourier domain. We then study and ...

This paper proposes the use of Gaussian Mixture Models to estimate conditional probability density functions in an environmental risk mapping context. A conditional Gaussian Mixture Model has been compared to the geostatistical method of Sequential Gaussian Simulations and shows good performances in reconstructing local PDF. The data sets used for this comparison are parts of the digital elevat...

Assessment of a DEM’s quality is usually undertaken by deriving a measure of DEM accuracy – how close the DEM’s elevation values are to the true elevation. Measures such as Root Mean Squared Error and standard deviation of the error are frequently used. These measures summarise elevation errors in a DEM as a single value. A more detailed description of DEM accuracy would allow better understand...

A new agricultural flood losses prediction method using digital elevation data combined with agricultural economic data is presented. The method is based on dynamically simulating the procedure of flood out. An example in Huangdunhu flood detention area, Jiangshu province of China has been given to describe how to use it to predict the incoming agricultural losses. Compared with prior methods, ...

15 16 Tidal Flats are important examples of extensive areas of natural environment that remain 17 relatively unaffected by man. Monitoring of tidal flats is required for a variety of 18 purposes. Remote sensing has become an established technique for the measurement of 19 topography over tidal flats. A further requirement is to measure topographic changes in 20 order to measure sediment budgets...

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...

This paper describes a new method for hypsometric tinting for small-scale maps. The method generalises digital elevation models by removing small unnecessary details and accentuating major valleys and ridgelines. The elevation data are filtered with lower and upper quartile filters that are combined using a drainage network. The lower quartile filter is applied in valleys, delimited by the drai...

We describe an approach for rendering large terrains in real-time. A digital elevation map defines the rough shape of the terrain. During rendering, procedural geometric and texture detail is added by the graphics hardware. We show, how quad meshes can be generated quickly that have a locally varying resolution that is optimized for the inclusion of procedural detail. We obtain these distorted ...

This article presents an algorithm that determines safe motions for an articulated rover on rough terrains. It relies on the evaluation of a set of elementary trajectories on a digital elevation map built as the rover moves. The algorithm relies on the explicit computation of geometric constraints on the rover chassis. It has been integrated within a continuously running navigation loop on boar...

Hack’s law is reviewed, emphasizing its implications for the elongation of river basins as well as its connections with their fractal characteristics. The relation between Hack’s law and the internal structure of river basins is investigated experimentally through digital elevation models. It is found that Hack’s exponent, elongation, and some relevant fractal characters are closely related. Th...