User Defined Topological Predicates in Database Systems

GeoInformatica, Volume 14, Number 1 / January, 2010

Thomas Behr and Ralf Hartmut Güting

“Current database systems cannot only store standard data like integer, string, and real values, but also spatial data like points, lines, and regions. The importance of topological relationships between spatial objects has been recognized a long time ago. Using the well known 9-intersection model for describing such relationships, a lot of different topological relationships can be distinguished. For the query language of a database system it is not desirable to have such a large number of topological predicates. Particularly the query language should not be extended by a lot of predicate names. It is desirable to build new relationships from existing ones, for example to coarse the granularity. This paper describes how a database system user can define and use her own topological predicates. We show algorithms for computing such predicates in an efficient way. Last, we compare these general versions with specialized implementations of topological predicates.”

A GIS-Based Comparison of the Mexican National and IUCN Methods for Determining Extinction Risk

Conservation Biology, Volume 23 Issue 5, Pages 1156 – 1166, Published Online: 19 May 2009


“The national systems used in the evaluation of extinction risk are often touted as more readily applied and somehow more regionally appropriate than the system of the International Union for Conservation of Nature (IUCN). We compared risk assessments of the Mexican national system (method for evaluation of risk of extinction of wild species [MER]) with the IUCN system for the 16 Polianthes taxa (Agavaceae), a genus of plants with marked variation in distribution sizes. We used a novel combination of herbarium data, geographic information systems (GIS), and species distribution models to provide rapid, repeatable estimates of extinction risk. Our GIS method showed that the MER and the IUCN system use similar data. Our comparison illustrates how the IUCN method can be applied even when all desirable data are not available, and that the MER offers no special regional advantage with respect to the IUCN regional system. Instead, our results coincided, with both systems identifying 14 taxa of conservation concern and the remaining two taxa of low risk, largely because both systems use similar information. An obstacle for the application of the MER is that there are no standards for quantifying the criteria of habitat condition and intrinsic biological vulnerability. If these impossible-to-quantify criteria are left out, what are left are geographical distribution and the impact of human activity, essentially the considerations we were able to assess for the IUCN method. Our method has the advantage of making the IUCN criteria easy to apply, and because each step can be standardized between studies, it ensures greater comparability of extinction risk estimates among taxa.”

Multitemporal Monitoring of Water Resources Degradation at Al-Azraq Oasis, Jordan, Using Remote Sensing and GIS Techniques

International Journal of Global Warming, 2010 – Vol. 2, No.1 pp. 1 – 16

Naser Kloub, Mohammed Matouq, Monzer Krishan, Saeid Eslamian, and Monther Abdelhadi

“The historical topographic maps and satellite images of Al-Azraq Oasis of Jordan were collected from 1953 to 2005. These images are demonstrated for the first time. The satellite land image for 2005 is considered to be the most significant one. This is considered to be the highest level of degradation since 1953. The water degradation in the lake was fitted by linear regression and the best fitting for the calculated surface area for the water can be presented by a polynomial equation.”

Roles of Digital Technology in China’s Sustainable Forestry Development

International Journal of Sustainable Development & World Ecology, 1745-2627, Volume 16, Issue 2, 2009, Pages 94 – 101

Lina Tang; Guofan Shao; Limin Dai

“China has the fifth largest forest area in the world and any change in China’s forestry development will have inevitable impacts on global ecological sustainability. China has undergone excessive logging of natural forests and also made tremendous efforts in afforestation during the past half century. China’s forestry is now going through a variety of transitions and several forestry programs have been implemented to drive forestry transitions. The goal of these actions is to protect ecological services of forests and sustain China’s forestry development. These forestry programs are spatially sophisticated and cannot be successfully implemented without accurate and transparent forest/forestry information. A variety of digital technologies, including forest modeling, remote sensing, geographic information systems, global positioning systems, and visualization, have been applied in handling diverse information in China’s forestry. Digital forestry is not just a theoretical concept in China. Our digital forestry experience in northeast China suggests that digital technology is both usable and useful in China’s forestry development. Digital technology is playing an important interactive role in China’s top-down forestry administration system. The analog-to-digital transition in technology is expected to lead to the success of forestry programs and forestry transitions in China.”

Adaptation to Climate Change in Regional Australia: A Decision-Making Framework for Modelling Policy for Rural Production

Geography Compass, Vol. 5, April 2010

Victor Sposito, Kurt Benke, Claudia Pelizaro, and Ray Wyatt

“A decision-making framework was developed and applied in regional Australia to identify adaptation issues arising in agricultural systems and rural production as a consequence of climate change. Australian agriculture is very susceptible to the adverse impacts of climate change, with major shifts in temperature and rainfall projected. An advantage of the framework is that it provides a suite of tools to aid in the formulation of strategies for sustainable regional development and adaptation. The decision-making framework uses a participatory approach that integrates land suitability analysis with uncertainty analysis and spatial optimisation to determine optimal agricultural land use (at a regional scale) for current and possible future climatic conditions. It thus provides a robust analytic approach to (i) recognise regions under threat of productivity declines, (ii) identify alternative cropping systems better adapted to likely future climatic conditions and (iii) investigate policy actions to improve the sub-optimal situations created by climate change. The decision-making framework and its methods were applied in a case study of the South West Region of Victoria.”