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Digital models of topographic elevation data form an integral part of geographic information systems (GIS) and are most often used for (1) hydrological modelling including flood simulation, delineation and analysis of watersheds and drainage networks, (2) soil erosion and sediment transport modelling, (3) delineation and study of physiographic units, (4) soil and ecological studies, (5) geomorphological evaluation of landforms, (6) civil engineering and military applications such as site and route selection, landslide hazard assessment, visibility analysis (viewshed analysis), and (7) remotely sensed image enhancement for 3D analysis. Groundwater and climatic models also use digital topographic data as essential components. Digital elevation models provide an opportunity to characterise quantitatively land surface in terms of slope gradient and curvature and yield digital terrain information not blurred by land cover features which is often a problem in stereo-aerial photograph interpretation and remotely sensed image analysis. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present two Open Source applications — R (programming environment for data analysis and graphics) and GRASS (geographic resources and analysis support system) Open Source Free GIS. Even-though there is a plethora of GIS and statistical applications on the market, the two applications are among the leaders in Open Source statistical and GIS solutions(l). Both are well-suited for research, educational purposes and for studies where non-trivial analyses are required. Moreover, sophisticated algorithms make them the right choice for scientists, and access to the source code makes them the right choice for those who can alter the code and suit it for specific purposes. [ABSTRACT FROM AUTHOR]

This paper focuses only on the technical details of the usage and creation of PDD. More details on the theory can be found in the papers written by (1998) and (2000). The Potential Drainage Density index, abbreviated as PDD, can be used for geomorphologic, pedologic and geologic characterisation of the landscape. [ABSTRACT FROM AUTHOR]

Solar energy is the main driver of natural processes on the Earth surface. It is an important input parameter into environmental, ecological and risksimulation models as the energy budget at the land surface and depends on the terrain. Vegetation biodiversity, and biomass production are also related to the radiation input. [ABSTRACT FROM AUTHOR]

The EU Water Framework Directive — integrated river basin management for Europe — puts great emphasis upon conservation considerations, the maintenance and development of water ecosystems, terrestrial ecosystems dependent on water and wetlands, focusing on the increasing demand from citizens and environmental organisations for sustainable water management [ABSTRACT FROM AUTHOR]

Soil data of various scales is needed for good management of agricultural and environmental resources. On the European level soil information is used for crop monitoring, yield forecasting, agricultural planning, feasibility studies for rural development, natural hazards forecasting, such as floods and landslides or slowly acting processes such as erosion, acidification and other types of chemical, biological and physical degradation of soils. However, no soil database for the European Union to support these goals had existed before the late eighties. The strong need for policy support has speeded up the database compilation and resulted in the first version of the Soil Geographical Database of Eurasia at scale 1:1 million (SGDBE1M). Despite its limitations, SGDBE1M is still among the few databases which serve as a flagship in the development of the small scale spatial databases in Europe. The version 2.0 of SGDBE1M was published recently, in 2004. The refinement of the database and the extension of its geographic coverage to Eurasia and the Mediterranean Africa are in preparation (ESB 2004) [ABSTRACT FROM AUTHOR]

In the last decade Europe has experienced a number of unusually longlasting rainfall events that produced severe floods, e.g. in the Netherlands, Belgium, France and Germany in 1993 and 1995, the Czech Republic, Poland and Germany in 1997, in North Italy (in 1994 and 2000), in the UK (e.g. in 1998 and 2000), Tisza (in 2000 and 2001), in the Elbe and Danube in 2002, and in 2005 in Romania and the northern Alpine region. There seems to be a trend of increasing flood hazard. This may support projections of future climate indicating that further increases in severe floods in North and Northwest Europe are likely (e.g. IPCC 2001). The Joint Research Centre of the European Commission (JRC) provides EU policy support on flood issues, especially focused on cross-border river basins. In addition to the work on the development of an early warning system at the pan-European scale (EFAS, the European Flood Alert System), JRC carries out flood mitigation and forecasting case studies in the Elbe and Danube catchments, and flash floods, climate change effects and flood risk mapping at European scale [1]. [ABSTRACT FROM AUTHOR]

Mathematical morphology can be defined as a theory for the analysis of spatial structures. It is called morphology because it concentrates on the form, shape, and size of the structures. It is mathematical in the sense that the analysis is based on set theory, integral geometry, and lattice algebra. When applied to digital spatial data, mathematical morphology offers a wide variety of methods and algorithms to solve scientific and practical problems. [ABSTRACT FROM AUTHOR]

Flooding is the major disaster affecting many countries in the world year after year. It is an inevitable natural phenomenon occurring from time to time in all rivers and natural drainage systems. Floods not only damage lives, natural resources and the environment, but they also cause losses to economy and health. Damage from flooding has been increasing each year resulting in loss of lives, property and production as well as affecting activities in the flooded areas. Large scale and long duration floods can be considered as the cause for economic loss to the concerned countries. [ABSTRACT FROM AUTHOR]

The availability of a European-wide database of consistent and hierarchically structured river networks and associated drainage basins is a major asset for the implementation and follow-up of environmental policies in the European Union and an important basis for international modelling and monitoring activities. In fact, drainage basins are important reference units for many biophysical processes and rivers represent major transport networks not only for water, but also for sediments, nutrients and pollutants. [ABSTRACT FROM AUTHOR]

"The Shuttle Radar Topography Mission (SRTM) obtained elevation data on a near-global scale to generate the most complete high-resolution digital topographic database of Earth' [1]. Availability to the publiC., uniform cover of the Earth's surface combined with a cell size acceptable for medium-scale soil modelling (90m on average) introduced the SRTM digital elevation model (DEM) as promising datasets for small and medium scale soil-landscape modelling and applications. [ABSTRACT FROM AUTHOR]

Terrain geomorphometric properties are major input parameters for majority of GIS-supported topographic models and applications such as erosion-deposition model, solar radiation model (Suri and Hofierka 2005), soil erosion model or river basin modelling (De Roo et al. 2000) [ABSTRACT FROM AUTHOR]

Quality of data used in the GIS-support tools is a critical issue, as the decisions that affect locations or areas are to be made effectively, in time and with adequate accuracy. At present, a number of European Union and national policy strategies rely on the use of quality digital elevation model (DEM) data. The accuracy, smoothness and representativeness are properties of DEM determining outputs of the support systems that are designed for assessment of renewable energy resources, flood forecasting, disaster and security management. Similarly, suitability analysis, calculating of environmental indicators and water quality monitoring within the catchments are based on the use of DEM and the decisions taken have financial and legal implications. Thus, a prerequisite for full exploitation of the potential of DEMs is to make them available for the community at sufficient accuracy and detail for a variety of applications. [ABSTRACT FROM AUTHOR]