DCGISTAM 2018 Abstracts

Short Papers
Paper Nr: 1

Integration of Remote Sensing Data to Facilitate Multi-Hazards Risk Assessments in Coastal Regions


Eduardo R. Oliveira, Leonardo Disperati and Fátima L. Alves

Abstract: This research is a development in the field of Geomatics applied to risk assessment. The main objective is to develop a methodology for multi-hazard assessments at the regional scale, based on satellite remote sensing. It aims to provide a tool to support the prevention and mitigation of environmental disasters, simultaneously capable of copping with multiple hazard sources and exposed elements overlapping in time and space. The study area is the Aveiro region (in the Northwest of Central Portugal), chosen because of its natural and anthropogenic pressures, which has been widely studied in terms of its vulnerabilities and exposure to several sources of hazards, such as floods, coastal overtopping, coastal and soil erosion and wildfires. This research started with the characterization of such events, privileging satellite imagery and remote sensing techniques to obtain variables to incorporate in corresponding single-hazard risk assessment methods. Afterwards, this models will simplified in order to discard any non-essential parameters in order to integrate exclusively data obtained from satellite imagery. These simplifications will be analyzed and validated through comparison with other studies using classical methods. Lastly, all models will be merged in a single multi-hazard methodology, resulting in a less demanding process in terms of time and resources requirements, with the potential of incorporation in a single product oriented for permanent updates and easy access for territorial planners and decision makers. This research meets several national and European strategic goals, contributing to increase the resilience of territories.

Paper Nr: 2

Reconstruction of Piecewise-explicit Surfaces from Three-dimensional Polylines - Applications in Seismic Interpretation in Compressive Domain


Joseph Baudrillard, Sébastien Guillon, Jean-Marc Chassery, Michèle Rombaut and Kai Wang

Abstract: Oil and gas exploration relies heavily on the knowledge of the underground structure. By conducting seismic reflection surveys, an image of the subsurface is obtained in the form of a 3D "cube", on which geological objects are interpreted. Amongst them, deposition surfaces (called horizons) are numerically modelized in order to assess the economical potential of a hydrocarbon field. The use of geo-referenced heightmaps is standard practice to represent horizons as they are mostly horizontal surfaces. In our context a heightmap is a geolocalized image, whose pixel values are a vertical elevation distance. However horizons are not always explicit; in other words, they cannot be projected vertically on a heightmap anymore. Yet many geological structures lead to the interpretation of such horizons, for example inverse faults in compressive domain. They are called "multivalued" as several height values are associated to the surface at some locations on the heightmap. For practical reasons, horizons are typically defined by hand-picked polylines. They are then vertically projected on a heightmap as pixels that are interpolated in a process called "gridding", in order to create a dense continuous surface. A new model is therefore required in order to represent a multivalued horizon, as well as methods to reconstruct it by interpolation from sparse three dimensional polylines. Triangulation and seismic attributes will also be adapted to the new model developped for gridding.

Paper Nr: 3

Polycentric Climate Governance and the Amazon Tipping Point - Indigenous Climate Governance in Acre-Brazil and Ucayali-Peru


Fronika Claziena Agatha de Wit

Abstract: The Amazon region faces complex challenges to the sustainable use of land and water resources because of its expanding socio-economic growth, infrastructure, and agricultural activities. Research shows that the Amazon may be moving towards a near-term tipping point: forest dieback might turn the forest from carbon sink to carbon emitter. Reducing emissions from deforestation, while at the same time keeping up agricultural production, is a major challenge for environmental governance. Top-down strategies fail to align the diverse levels and sectors of government and exclude local stakeholders from the process. New bottom-up forms of climate governance, with polycentric patterns, provide an innovative framework for multi-level governance. Polycentricity highlights the importance of vertical and horizontal integration as well as learning-by- doing. This study examines the challenges, potentials and co-benefits of polycentric governance for Low-Emission Rural Development (LED-R) and looks for sustainable pathways to prolong the Amazonian tipping point. As examples of polycentric governance in the Amazon, this research evaluates the adaptive capacity of three Brazilian Amazon States and local (indigenous) adaptation strategies. By doing so, this study moves beyond the Amazon´s ecological planetary boundary and includes the people living in the Amazon. It examines not only the boundaries for a sustainable landscape, but, more importantly, looks at a threshold for a sustainable territory. The Amazonian people have an important role in climate governance in order to prevent the Amazon´s tipping point.