A geographic knowledge discovery approach to property valuation

This thesis involves an investigation of how knowledge discovery can be applied in the area Geographic Information Science. In particular, its application in the area of property valuation in order to reveal how different spatial entities and their interactions affect the price of the properties is explored. This approach is entirely data driven and does not require previous knowledge of the area applied. To demonstrate this process, a prototype system has been designed and implemented. It employs association rule mining and associative classification algorithms to uncover any existing inter-relationships and perform the valuation. Various algorithms that perform the above tasks have been proposed in the literature. The algorithm developed in this work is based on the Apriori algorithm. It has been however, extended with an implementation of a ‘Best Rule’ classification scheme based on the Classification Based on Associations (CBA) algorithm. For the modelling of geographic relationships a graph-theoretic approach has been employed. Graphs have been widely used as modelling tools within the geography domain, primarily for the investigation of network-type systems. In the current context, the graph reflects topological and metric relationships between the spatial entities depicting general spatial arrangements. An efficient graph search algorithm has been developed, based on the Djikstra shortest path algorithm that enables the investigation of relationships between spatial entities beyond first degree connectivity. A case study with data from three central London boroughs has been performed to validate the methodology and algorithms, and demonstrate its effectiveness for computer aided property valuation. In addition, through the case study, the influence of location in the value of properties in those boroughs has been examined. The results are encouraging as they demonstrate the effectiveness of the proposed methodology and algorithms, provided that the data is appropriately pre processed and is of high quality

A Critical Evaluation of Remote Sensing Based Land Cover Mapping Methodologies

A novel, disaggregated approach to land cover survey is developed on the basis of land cover attributes; the parameters typically used to delineate land cover classes. The recording of land cover attributes, via objective measurement techniques, is advocated as it eliminates the requirement for surveyors to delineate and classify land cover; a process proven to be subjective and error prone. Within the North York Moors National Park, a field methodology is developed to characterise five attributes: species composition, cover, height, structure and density. The utility of land cover attributes to act as land cover ‘building blocks’ is demonstrated via classification of the field data to the Monitoring Landscape Change in the National Parks (MLCNP), National Land Use Database (NLUD) and Phase 1 Habitat Mapping (P1) schemes. Integration of the classified field data and a SPOT5 satellite image is demonstrated within per-pixel and object-orientated classification environments. Per-pixel classification produced overall accuracies of 81%, 80% and 76% at the field samples for the MLCNP, NLUD and P1 schemes, respectively. However, independent validation produced significantly lower accuracies. These decreases are demonstrated to be a function of sample fraction. Object-orientated classification, exemplified for the MLCNP schema at 3 segmentation scales, achieved accuracies approaching 75%. The aggregation of attributes to classes underutilises the potential of the remotely sensed data to describe landscape variability. Consequently, classification and geostatistical techniques capable of land cover attribute parameterisation, across the study area, are reviewed and exemplified for a sub-pixel classification. Land cover attributes provide a flexible source of field data which has been proven to support multiple land cover classification schemes and classification scales (sub-pixel, pixel and object). This multi-scaled/schemed approach enables the differential treatment of regions, within the remote sensing image, as a function of landscape characteristics and the users’ requirements providing a flexible mapping solution

Dwelling on ontology - semantic reasoning over topographic maps

The thesis builds upon the hypothesis that the spatial arrangement of topographic features, such as buildings, roads and other land cover parcels, indicates how land is used. The aim is to make this kind of high-level semantic information explicit within topographic data. There is an increasing need to share and use data for a wider range of purposes, and to make data more definitive, intelligent and accessible. Unfortunately, we still encounter a gap between low-level data representations and high-level concepts that typify human qualitative spatial reasoning. The thesis adopts an ontological approach to bridge this gap and to derive functional information by using standard reasoning mechanisms offered by logic-based knowledge representation formalisms. It formulates a framework for the processes involved in interpreting land use information from topographic maps. Land use is a high-level abstract concept, but it is also an observable fact intimately tied to geography. By decomposing this relationship, the thesis correlates a one-to-one mapping between high-level conceptualisations established from human knowledge and real world entities represented in the data. Based on a middle-out approach, it develops a conceptual model that incrementally links different levels of detail, and thereby derives coarser, more meaningful descriptions from more detailed ones. The thesis verifies its proposed ideas by implementing an ontology describing the land use ‘residential area’ in the ontology editor Protégé. By asserting knowledge about high-level concepts such as types of dwellings, urban blocks and residential districts as well as individuals that link directly to topographic features stored in the database, the reasoner successfully infers instances of the defined classes. Despite current technological limitations, ontologies are a promising way forward in the manner we handle and integrate geographic data, especially with respect to how humans conceptualise geographic space

Soil biodiversity: functions, threats and tools for policy makers

Human societies rely on the vast diversity of benefits provided by nature, such as food, fibres, construction materials, clean water, clean air and climate regulation. All the elements required for these ecosystem services depend on soil, and soil biodiversity is the driving force behind their regulation. With 2010 being the international year of biodiversity and with the growing attention in Europe on the importance of soils to remain healthy and capable of supporting human activities sustainably, now is the perfect time to raise awareness on preserving soil biodiversity. The objective of this report is to review the state of knowledge of soil biodiversity, its functions, its contribution to ecosystem services and its relevance for the sustainability of human society. In line with the definition of biodiversity given in the 1992 Rio de Janeiro Convention, soil biodiversity can be defined as the variation in soil life, from genes to communities, and the variation in soil habitats, from micro-aggregates to entire landscapes. Bio Intelligence Service, IRD, and NIOO, Report for European Commission (DG Environment

Impact des ressources florales et de nidification sur l'écologie de butinage et la structure des communautés des pollinisateurs à travers des paysages perturbés

Today, our societies are increasingly concerned about the alarming disappearance of insects. Yet they are essential to the proper functioning of our ecosystems, our food and our health. Pollinating insects such as bees, hoverflies and apoid wasps are also affected by this collapse. These insects generate significant ecosystem services for agriculture and the maintenance of natural areas through the pollination of flowering plants and the biological control of crops. A series of causes for these collapses have been widely documented in scientific literature, and it appears that it is mainly landscape degradation that is causing the greatest damage to biodiversity. Agricultural intensification and urbanization are converting complex natural areas into homogeneous, anthropogenic zones, thereby destroying floral and nesting resources, which are key components in the development and maintenance of pollinating insect communities. The homogenization of the landscape also alters the foraging behavior of our pollinating insects. It is in this context that this research thesis will focus, through 4 case studies, on the impact of landscape fragmentation on pollinator communities and foraging ecology in temperate zone of agricultural and urban landscapes. This thesis is structured around a general introduction (Chapter I), a general methodology (Chapter II) which introduces the technical tools shared between the different case studies, and four chapters constituting the core of this thesis (Chapter III-VI), the first two of which focus on agricultural landscapes, while the last two are more concerned with urban environments. The thesis concludes with a discussion, an outlook on future research and a general conclusion (Chapter VII). Chapter III looks at the influence of ecological diversification on the biodiversity of pollinators, particularly wild bees and hoverflies, on two farms in the early stages of ecological transition. This study has the merit of providing quality pollinator occurrence data based on standardized sampling techniques established over two years (2018-2019) and reports certain species that may be of conservation concern given their critical conservation status. In view of the specific diversity of wild bees present (101 species) and hoverflies (31 species), the ecological diversification of environments within the two sampled farms (e.g. wetlands, flower strips...) and agroecological practices may constitute new favorable environments for rare, oligolectic or endangered pollinator species. Building on the methodology and results of the previous chapter, in chapter IV we looked at the impact of a more specific floral resource supply practice: flower strips in intercropping systems with winter wheat. We found that a multifloral composition of flower strips attracted a greater diversity of hoverflies but not wild bees than monofloral oleaginous strips composed of Dimorphoteca pluvialis (Asteraceae) and Camelina sativa (Brassicacea). Finally, the ecological and economic benefits provided by these oleaginous flower strips are organized on three levels: (i) they provide alternative floral resources to pollinators; (ii) farmers are rewarded by the Agro-Environmental and Climate Measures (MAEC) of the European Union's Common Agricultural Policy; (iii) and farmers can generate additional income from the resale of harvested oleaginous seeds. In chapter V, we investigate urban landscapes. Pollen availability is a key factor influencing the population dynamics of pollinating insects in urban disturbed landscapes. In this study, we analyzed the foraged floral resources of honeybee colonies, Apis mellifera L., along an urban-rural gradient in a mega-city Tokyo (Japan). After a genomic analysis (i.e., metabarcoding) to identify the floral species foraged on the pollen samples, we showed that the landscape factor explains the differences in composition of the flowers visited and not their specific richness, whereas this richness is significantly dependent on the temporal factor. Honeybees forage more on woody species in spring, and more on herbaceous species in autumn. This study provides us with a better understanding of the urban needs of honeybees in a mega-city. Urban surfaces are commonly perceived as "ecologically impermeable" and can therefore represent a considerable obstacle to nesting opportunities for ground-nesting insects. In Chapter VI, we looked at the nesting alternative that pavements could offer for a range of ground-nesting Hymenoptera in the city of Brussels-Capital. Our study identified 22 species of wild bees and apoid wasps capable of nesting on Brussels sidewalks. These species mainly nested in old Brussels sidewalks made of sandstone pavers or concrete slabs with unbonded joints averaging one centimeter in width, and where the construction layers beneath the sidewalks were sandy in texture. At the end of this experiment, we were able to design technical recommendations and management practices to encourage these pollinating insects. The relevance of this research project and the general context are discussed at the end of this thesis in Chapter VII. Taken as a whole, these four studies underline the importance of food and nesting resources for insect pollinator communities and constitute milestones of knowledge providing further arguments in favor of the conservation and restoration of insect pollinators in disturbed environments We concluded this discussion with an open-minded outlook for the continuation scientific work in these topics of agricultural and urban ecology