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de Man W.H.E.,International Institute for Geo information Science and Earth Observation ITC
Transactions in GIS | Year: 2013

Notwithstanding optimistic rhetoric about integrating geospatial data from different sources and supporting good governance, much of the literature on geoinformation management is limited to a technical orientation with a positivist paradigm. Complex geoinformation management, like public policy, must go beyond these boundaries. The article calls attention to the underexposed role of dilemmas in geoinformation management and how to cope with them. It uses lessons from the development of 'integrated surveys' at the former International Training Centre for Aerial Survey (ITC) in The Netherlands as an early and practical case of managing geoinformation for public policy some 40 years ago. These lessons are apparently also relevant to modern digital geoinformation management, as in SDI. Focus on public policy requires not only integration of geospatial data from different sources but also integration of geoinformation into complex decision-making processes. This complexity probably creates dilemmas because of mutually incompatible perspectives between different actors on what is to be managed. Geoinformation management for public policy therefore requires the ability to find, over and over again, a common ground between and beyond incompatible perspectives. The article proposes a 'transdisciplinary' framing of geoinformation management to support the required thinking outside the box. © 2013 John Wiley & Sons Ltd.

Nefeslioglu H.A.,General Directorate of Mineral Research and Exploration | Gokceoglu C.,Hacettepe University | Sonmez H.,Hacettepe University | Gorum T.,International Institute for Geo information Science and Earth Observation ITC
Landslides | Year: 2011

The main purpose of this study is to develop a new hazard evaluation technique considering the current limitations, particularly for shallow landslides. For this purpose, the Buyukkoy catchment area, located in the East Black Sea Region in the east of Rize province and the south of Cayeli district, was selected as the study area. The investigations were executed in four different stages. These were (1) preparation of a temporal shallow landslide inventory of the study area, (2) assessment of conditioning factors in the catchment, (3) susceptibility analyses and (4) hazard evaluations and mapping. A total of 251 shallow landslides in the period of 1955-2007 were recognised using different data sources. A 'Sampling Circle' approach was proposed to define shallow landslide initiation in the mapping units in susceptibility evaluations. To accomplish the susceptibility analyses, the method of artificial neural networks was implemented. According to the performance analyses conducted using the training and testing datasets, the prediction and generalisation capacities of the models were found to be very high. To transform the susceptibility values into hazard rates, a new approach with a new equation was developed, taking into account the behaviour of the responsible triggering factor over time in the study area. In the proposed equation, the threshold value of the triggering factor and the recurrence interval are the independent variables. This unique property of the suggested equation allows the execution of more flexible and more dynamic hazard assessments. Finally, using the proposed technique, shallow landslide initiation hazard maps of the Buyukkoy catchment area for the return periods of 1, 2, 5, 10, 50 and 100 years were produced. © 2011 Springer-Verlag.

Verstappen H.T.,International Institute for Geo information Science and Earth Observation ITC
Geografia Fisica e Dinamica Quaternaria | Year: 2011

Natural hazards, threatening many parts of the world, are often ignored in the context of regional planning and environmental management, although this is necessary for avoiding, or at least substantially reducing the recurrence interval and magnitude of the related «natural» disasters. This is particularly the case for «creeping» disasters, related to environmental degradation caused by slow and in many cases almost imperceptible processes, including desertification, salinization, certain forms of soil erosion, pollution, etc. The more spectacular instantaneous disasters, resulting from high-intensity and low-frequency natural events of endogenous or exogenous origin, are nowadays reported about by the media world-wide. They are, however, soon out of focus again and adequate measures to prevent similar disasters in the future do not always remain a high priority of the responsible authorities. Disaster reduction through environmental management is a complex issue that requires interdisciplinary applied research related to the natural environment as well as to the socio-economic situation of the endangered societies. In fact, sustainability is at stake. For the implementation of adequate protection measures, ranging from «hard» engineering structures to «soft» management improvements, optimal cooperation between the various sectors of the communities concerned is essential. This multisectoral approach should lead up to a master-plan for long term regional management and a disaster scenario specifying tasks and responsibilities of organizations and individuals in case of an emergency situation. Apart from natural disasters, technical-industrial disasters and also the, often neglected, ecological disasters should be considered. Humanitarian disasters are, unfortunately, largely outside the field of science. The UNIDNDR (International Decade for Natural Disaster Reduction) program of the 19nineties concentrated on natural disasters only. Its follow-up, the UN-ISDR (International Strategy for Disaster Reduction), has a broader scope because technological / industrial disasters are also included. Examples are given of volcanic disasters in Indonesia, including gas emanations on the Dieng plateau and pyroclastic flows on the densely populated SW slopes of the Merapi volcano in Central Java, Further, the effects of the ill-famed eruption of the Nevado de Ruiz volcano, Colombia in 1985 are discussed in relation to shortcomings in disaster mitigation systems. Drought and desertification studies executed in northern Chad and in Botswana are discussed thereafter as an introduction to the problems of assessing and achieving global sustainability problems.

Voinov A.,International Institute for Geo information Science and Earth Observation ITC | Cerco C.,U.S. Army
Environmental Modelling and Software | Year: 2010

Model integration is becoming increasingly important as our impacts on the environment become more severe and the systems we analyze become more complex. There are numerous attempts to make different models work in concert. However model integration usually treats models as software components only, ignoring the evolving nature of models and their constant modification and re-calibration to better represent reality. As a result, the changes that used to impact only contained models of subsystems, now propagate throughout the integrated system, across multiple model components. This makes it harder to keep the overall complexity under control and, in a way, defeats the purpose of modularity, where efficiency is supposed to be gained from independent development of modules. We argue that data that are available for module calibration can serve as an intermediate linkage tool, sitting between modules and providing a module-independent baseline, which is then adjusted when scenarios are to be run. In this case, it is not the model output that is directed into the next model. Rather, model output is presented as a variation around the baseline trajectory, and it is this variation that is then fed into the next module down the chain. The Chesapeake Bay Program suite of models is used to illustrate these problems and the possible remedy.

Carranza E.J.M.,International Institute for Geo information Science and Earth Observation ITC
Geochemistry: Exploration, Environment, Analysis | Year: 2010

In this study, continuous field models of geochemical landscapes were obtained by interpolating stream sediment geochemical data while discrete field models of geochemical landscapes were obtained by attributing stream sediment geochemical data to their sample catchment basins. This study aimed to: (1) compare and contrast anomaly maps derived from continuous and discrete field models of stream sediment geochemical landscapes; and (2) determine which empirical frequency distributions - those of original point data or those of pixels values in models of stream sediment geochemical landscapes - are more useful in mapping of anomalies in such geochemical landscapes. Anomalies were mapped by using the mean+2SDEV (standard deviation), median+2MAD (median absolute deviation) and concentration-area (C-A) fractal methods of identifying threshold values in a geochemical data set. The results of the study in the Aroroy gold district (Philippines) highlight the following findings. In mapping of anomalies in either continuous or discrete field models of stream sediment geochemical landscapes, the C-A fractal method performs best, followed by the median+2MAD method and then by the mean+2SDEV method. Anomalies mapped in discrete field models, compared to anomalies mapped in continuous field models, of stream sediment geochemical landscapes mostly have stronger positive spatial associations with the known epithermal Au deposit occurrences in the study area. Empirical frequency distributions of either the original point data or the pixels values in the models of stream sediment geochemical landscapes are similarly useful in applying the C-A fractal method, but not in applying either the median+2MAD or mean+2SDEV method, to map anomalies in either continuous or discrete field models of such geochemical landscapes. © 2010 AAG/Geological Society of London.

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