This thesis discusses matching of 3D surfaces, in particular, their registration in a common coordinate system. This differs from object recognition in the sense that the surfaces are generally close to registration, sometimes so close that the mismatch cannot be detected on visual inspection. The surface matching algorithm, based on least squares theory, is therefore an estimation of the matching parameters, sometimes very small, which provides the most statistically accurate registration. High redundancy is achieved with the algorithm, as each point of one surface can potentially participate in the formation of an observation equation for the least squares adjustment. The algorithm minimises the separation between the surfaces. The surfaces are defined by sets of points represented by their cartesian coordinates in 3D space, without restrictions on the mode of sampling used in the capture of the data. The registration is executed without control points. Modern non-thematic sampling methods, for instance airborne laser scanning, can benefit from such an algorithm. Other applications include processes where permanent control markers cannot be used, for example, medical applications or coastal erosion. Surface matching has been used previously by a small number of people. The particular interest of this thesis, however, has been to test the accuracy and other characteristics of the matching, especially when weighting is used with the surface separations. This thesis presents and compares several weighting techniques including one technique based on the covariance function. In addition, a statistical method to model matching accuracy as a function of the density of the control surface is formulated. The method is useful to ascertain the interpolation component of the matching error. The remaining component of the error can be deducted and analysed according to the project under consideration. Examples of project might be filtering in data fusion assessment, or volume displacement in landslide analysis. The theory is developed using artificial data. This helps to isolate and analyse in turn the various characteristics of the surface matching. The thesis is then illustrated with examples involving real data sampled in Newcastle, NSW, Australia, using methods such as ALS, photogrammetry and GPS. / PhD Doctorate

The ability to visually explore the world is a substantial and crucial factor for humans to interact and navigate in their environment. Given the importance of the visual system, it is no wonder that vision research has become one of the major fields in cognitive science. Eye tracking studies hereby revealed three main factors, that guide our visual perception and attention. These factors can be described as bottom-up and top-down features, as well as spatial properties. Whereas previous research has put a lot of effort in investigating each of these factors in detail, the combined interaction of the factors - especially regarding spatial properties and biases - is less well understood. This thesis deals with the different aspects of several features influencing visual behavior. I present four studies that examine different aspects of images with respect to their spatial properties. Hereby, I elaborate the global salience of images as spatial factor, which can be impacted by top-down features, such as emotions. Further, I describe how the effect of image sizes as a spatial property is linked with visual exploration and exploitation. In study 1 (Chapter 2) we investigated the global salience of images and its properties. While recording of eye movements, participants freely observed several image pairs, where one image has been shown on the left, and one image on the right side of the screen. Based on results of the eye tracking recordings, we trained a logistic regression model to calculate a global salience coefficient for each image that can be ranked in order to predict the location - left or right image - of the first fixations in an image pair. Our trained model was able to accurately predict the first fixation of an image pair, indicating that images indeed provide a unique global salience score. Hereby, we showed that the global salience of an image is independent of local salience and further that a given task or familiarity of the images affected the respective global salience. In study 2 (Chapter 3) we investigated the influence of emotions as top-down factor on natural visual behavior. Participants had been emotionally primed either by a sequence of positive or negative laden images. Afterwards, we recorded participants' eye movements while being confronted with image pairs, were one positive and one negative image - left and right respectively - was presented simultaneously. Results showed that positively primed participants tended to shift overt attention towards negative images in the stimulus pairs. In a later memory request, we further showed that such participants had better recall performance of negative image content. Thus, we concluded that positive priming increases attention and memory towards negative content. In study 3 (Chapter 4) we investigated the trade-off between the exploration (i.e. initiate fixations to unseen image areas) and exploitation (i.e. stay and process the currently fixated information in depth) of natural images with varying sizes. Participants freely observed images of different sizes and categories while eye movements have been recorded. For exploration we tested the distribution of fixations measured by the central tendency and entropy, as well as number of fixations and saccade amplitudes. The exploitation was derivated from the fixation duration. In our results, we found that larger image sizes led to a shift from exploitation towards exploration. That is, images have been explored more broaden while in-depth processing reduced accordingly. In study 4 (Chapter 5) we investigated the effect of image sizes in natural viewing behavior within patients suffering from retinitis pigmentosa (RP); an inherited disease that causes progressive peripheral visual-field loss. The purpose of this study was to examine whether visual behavior differed when the scene content was shown in various extents of the perceived visual field. For this, participants with varying degrees of visual-field loss and healthy control participants freely observed images of different sizes while eye movements were recorded. For healthy control participants we could replicate the effects already described in Chapter 4. That is, larger images lead to a shift from exploitation to exploration. Surprisingly, on group level RP patients scanned the images similar to the healthy control participants. However, on individual level RP patients also showed individual idiosyncratic explorative strategies when the observed scene exceeded their visible field. We thus concluded, that although retinitis pigmentosa leads to a severe loss of the visual field, there seems to be no general adaptive mechanism adapting visual exploration accordingly. Instead, individuals rely on individual strategies, leading to high heterogeneity in the RP group. In a nutshell, our results showed that images provide unique global salience coefficients that can predict attraction of visual attention. However, emotions as top-down factor affect these global salience coefficients as shown by a shift of attention towards negative image content. The size of an image as spatial property affects natural viewing behavior in such way that in-depth processing (exploitation) shifts towards broader exploration in large images. These results remain remarkably stable, even when the image size extends the visual field (in RP patients). Summarized, the studies in this thesis were motivated to gain and deepen knowledge in the interplay between distinct factors - with an emphasis on spatial properties - that impact visual behavior and attention.

Neste trabalho foram pesquisados os métodos e procedimentos utilizados na execução de obras das redes subterrâneas da infra-estrutura urbana, desde a demarcação até a elaboração da planta do levantamento de como construído. Os equipamentos utilizados na execução de obras, tanto os não destrutivos, como os destrutivos e aqueles de localização de dutos e cabos enterrados. São também apresentados e detalhados os procedimentos à luz das normas técnicas, para o devido georreferenciamento das redes de infra-estrutura subterrânea. Foram inclusive analisados os resultados obtidos para o posicionamento das redes, conforme apresenta o estudo de casos, em obras com a utilização de equipamentos para a localização de cabos e dutos enterrados. Finalmente são sugeridas propostas para o georreferenciamento das redes de infra-estrutura urbana com a finalidade de constituição de um cadastro único. / This study investigates the methods and procedures used in the urban infrastructure underground network, from the demarcation to the production of the as-built survey plant. The equipments used in the execution of services, as far as non destructive, destructive as well as in the localization of underground pipe and cables are concerned, are presented and the procedures are detailed for underground infrastructure network georeferencing, considering the standard norms. The results of the network positioning with the utilization of equipments for underground pipes and cables equipments are analysed, as shown in the case study. Finally, proposals for the urban underground network georeferencing are presented in order to build a unique cadastre.

<p>The freshwater pearl mussel (<em>Margaritifera margaritifera</em>) has declined dramatically throughout its range and is faced with recruitment problems in most of the streams where populations still persist. Human activities, such as forestry and agriculture, are thought to be the main reason for these problems. In this study, spatial information on landscape features along 38 streams with known recruitment status were analyzed in an effort to determine if GIS-tools could be used to identify streams with successful recruitment. Differences in the distribution of various landscape features, measured in stream corridors of 50 and 150 m, and differences in several water chemical factors between streams with and without recruitment were investigated. The distribution of landscape features was also compared with host fish (brown trout) density and any statistically significant water chemical factor.  Both mussel recruitment and trout density were found to be negatively related to clear-cuts, and mussel recruitment was also negatively related to high water color, which has been shown to be correlated with high nutrient content, one of several adverse effects of clear-cutting close to streams. Recruitment was expected to be negatively affected by roads, but no such relationship could be found. Instead, mussel recruitment was found to be positively related to the number of road crossings per kilometer, but the strength of this relationship was questionable. In addition, even though it was somewhat unclear, high proportions of lakes and ponds were found to be positive for both recruitment and high trout density. The results of the study indicate that GIS-tools can be used to find landscape features that affect recruitment of freshwater pearl mussel and they support the belief that forestry activities are an important cause for the decline of the species in Sweden. In addition, the results indicate that leaving protective zones of forest between streams and clear-cuts can be a possible conservation method for the freshwater pearl mussel.</p> / <p>Flodpärlmusslan (<em>Margaritifera margaritifera</em>) har minskat kraftigt i hela sitt utbredningsområde och i de flesta vattendrag där populationer finns kvar sker ingen rekrytering. Mänskliga aktiviteter, exempelvis skogsbruk och jordbruk, anses vara huvudorsaken för dessa problem. Syftet med den här studien var att undersöka om GIS-verktyg kan användas för att identifiera vattendrag med fungerande rekrytering. För att uppnå det analyserades geografisk information om landskapet längs 38 vattendrag med känd rekryteringsstatus. Skillnader i fördelningen av olika landskapsföreteelser, uppmätt i 50 och 150 meters buffertzoner, och skillnader i flera vattenkemiska faktorer mellan vattendrag med eller utan rekrytering undersöktes. Dessutom undersöktes även om det fanns något förhållande mellan landskapsföreteelser och tätheten av värdfisk (öring) och mellan landskapsföreteelser och signifikanta vattenkemiska faktorer. Både rekrytering av flodpärlmusslor och öringstäthet var negativt relaterad till kalhyggen. Rekrytering var också negativt relaterad till hög vattenfärg, som har visats vara korrelerat med högt näringsinnehåll, en av flera effekter kalhyggen nära vattendrag har. Rekrytering förväntades påverkas negativt av vägar, men inget negativt förhållande hittades. Istället hittades ett positivt förhållande mellan rekrytering och antalet vägkorsningar per kilometer, men styrkan av det förhållandet var ifrågasättbar. Dessutom var, om än något otydligt, andelen sjö och damm positivt för både rekrytering och hög öringtäthet. Studien indikerar att GIS-verktyg kan användas för att hitta landskapsföreteelser som påverkar rekryteringen av flodpärlmusslor och den stödjer bedömningen att skogsbruk är en av de viktigaste anledningarna till artens nedgång i Sverige. Dessutom indikerar resultaten att skyddszoner mellan kalhyggen och vattendrag kan vara en möjlig skyddsåtgärd för flodpärlmusslan.</p>

Reasoning about temporal and spatial information is a common task in computer science, especially in the field of artificial intelligence. The topic of this thesis is the study of such reasoning from a computational perspective. We study a number of different qualitative point based formalisms for temporal reasoning and provide a complete classification of computational tractability for different time models. We also develop more general methods which can be used for proving tractability and intractability of other relational algebras. Even though most of the thesis pertains to qualitative reasoning the methods employed here can also be used for quantitative reasoning. For instance, we introduce a tractable and useful extension to the quantitative point based formalism STP. This extension gives the algebra an expressibility which subsumes the largest tractable fragment of the augmented interval algebra and has a faster and simpler algorithm for deciding consistency. The use of disjunctions in temporal formalisms is of great interest not only since disjunctions are a key element in different logics but also since the expressibility can be greatly enhanced in this way. If we allow arbitrary disjunctions, the problems under consideration typically become intractable and methods to identify tractable fragments of disjunctive formalisms are therefore useful. One such method is to use the independence property. We present an automatic method for deciding this property for many relational algebras. Furthermore, we show how this concept can not only be used for deciding tractability of sets of relations but also to demonstrate intractability of relations not having this property. Together with other methods for making total classifications of tractability this goes a long way towards easing the task of classifying and understanding relational algebras. The tractable fragments of relational algebras are sometimes not expressive enough to model real-world problems and a backtracking solver is needed. For these cases we identify another property among relations which can be used to aid general backtracking based solvers to finnd solutions faster. / Article I is a revised and extended version of the following three papers: 1. Mathias Broxvall and Peter Jonsson. Towards a Complete Classification of Tractability in Point Algebras for Nonlinear Time. In Proceedings of the 5th International Conference on Principles and Practice of Constraint Programming (CP-99), pp. 129-143, Alexandria, VA, USA, Oct, 1999. 2. Mathias Broxvall and Peter Jonsson. Disjunctive Temporal Reasoning in Partially Ordered Time Structures. In Proceedings of the Seventeenth National Conference on Artificial Intelligence (AAAI-2000), pp. 464-469, Austin, Texas, USA, Aug, 2000. 3. Mathias Broxvall. The Point Algebra for Branching Time Revisited. In Proceedings of the Joint German/Austrian Conference on Artificial Intelligence (KI-2001), pp. 106-121, Vienna, Austria, Sep, 2001. --- Article II is a revised and extended version of the following paper: Mathias Broxvall, Peter Jonsson and Jochen Renz: Refinements and Independence: A Simple Method for Identifying Tractable Disjunctive Constraints. In Proceedings of the 6th International Conference on Principles and Practice of Constraint Programming (CP-2000), pp. 114-127, Singapore, Sep, 2000.

The freshwater pearl mussel (Margaritifera margaritifera) has declined dramatically throughout its range and is faced with recruitment problems in most of the streams where populations still persist. Human activities, such as forestry and agriculture, are thought to be the main reason for these problems. In this study, spatial information on landscape features along 38 streams with known recruitment status were analyzed in an effort to determine if GIS-tools could be used to identify streams with successful recruitment. Differences in the distribution of various landscape features, measured in stream corridors of 50 and 150 m, and differences in several water chemical factors between streams with and without recruitment were investigated. The distribution of landscape features was also compared with host fish (brown trout) density and any statistically significant water chemical factor.  Both mussel recruitment and trout density were found to be negatively related to clear-cuts, and mussel recruitment was also negatively related to high water color, which has been shown to be correlated with high nutrient content, one of several adverse effects of clear-cutting close to streams. Recruitment was expected to be negatively affected by roads, but no such relationship could be found. Instead, mussel recruitment was found to be positively related to the number of road crossings per kilometer, but the strength of this relationship was questionable. In addition, even though it was somewhat unclear, high proportions of lakes and ponds were found to be positive for both recruitment and high trout density. The results of the study indicate that GIS-tools can be used to find landscape features that affect recruitment of freshwater pearl mussel and they support the belief that forestry activities are an important cause for the decline of the species in Sweden. In addition, the results indicate that leaving protective zones of forest between streams and clear-cuts can be a possible conservation method for the freshwater pearl mussel. / Flodpärlmusslan (Margaritifera margaritifera) har minskat kraftigt i hela sitt utbredningsområde och i de flesta vattendrag där populationer finns kvar sker ingen rekrytering. Mänskliga aktiviteter, exempelvis skogsbruk och jordbruk, anses vara huvudorsaken för dessa problem. Syftet med den här studien var att undersöka om GIS-verktyg kan användas för att identifiera vattendrag med fungerande rekrytering. För att uppnå det analyserades geografisk information om landskapet längs 38 vattendrag med känd rekryteringsstatus. Skillnader i fördelningen av olika landskapsföreteelser, uppmätt i 50 och 150 meters buffertzoner, och skillnader i flera vattenkemiska faktorer mellan vattendrag med eller utan rekrytering undersöktes. Dessutom undersöktes även om det fanns något förhållande mellan landskapsföreteelser och tätheten av värdfisk (öring) och mellan landskapsföreteelser och signifikanta vattenkemiska faktorer. Både rekrytering av flodpärlmusslor och öringstäthet var negativt relaterad till kalhyggen. Rekrytering var också negativt relaterad till hög vattenfärg, som har visats vara korrelerat med högt näringsinnehåll, en av flera effekter kalhyggen nära vattendrag har. Rekrytering förväntades påverkas negativt av vägar, men inget negativt förhållande hittades. Istället hittades ett positivt förhållande mellan rekrytering och antalet vägkorsningar per kilometer, men styrkan av det förhållandet var ifrågasättbar. Dessutom var, om än något otydligt, andelen sjö och damm positivt för både rekrytering och hög öringtäthet. Studien indikerar att GIS-verktyg kan användas för att hitta landskapsföreteelser som påverkar rekryteringen av flodpärlmusslor och den stödjer bedömningen att skogsbruk är en av de viktigaste anledningarna till artens nedgång i Sverige. Dessutom indikerar resultaten att skyddszoner mellan kalhyggen och vattendrag kan vara en möjlig skyddsåtgärd för flodpärlmusslan.

The aim of this thesis was to explore the spatiality’s affect on refugee’s sense of safety in the Osire refugee settlement in Namibia. The gathered empirics together with previous research and theories should lead to a design for a spatial information system. The system should contribute to peoples’ understanding of their environments’ whole structure as well as showing the way to the health centre and the police station, thus increasing their sense of psychological and physical safety. A wish was also to breathe life into the point of intersection of spatial information design and human science. The methods used to enable this were first and foremost a field study in the settlement to experience and acquire first-hand information. In addition observation, introspection and several interviews were conducted. As a result I established safety to be an issue that could be solved with spatial design. Refugees expressed that not knowing your environment or finding your way leaves you scared, uncomfortable and confused. With the use of a spatial information system safety can literally be created, as demonstrated in the design proposal. The conclusion is that much could be done to spatially solve complex issues as long as it’s addressed from that perspective.

Though many researchers have suggested that 3D virtual environments (VEs) could provide advantages for conceptual learning, few studies have attempted to evaluate the validity of this claim. While many educational VEs share the challenge of providing learners with information within 3D spaces, few researchers have investigated what approaches are used to help learn new information from 3D spatial representations. It is not understood how well learners can take advantage of 3D layouts to help understand information. Additionally, although complex arrangements of information within 3D space can potentially allow for large amounts of information to be presented within a VE, accessing this information can become more difficult due to the increased navigational challenges. Complicating these issues are details regarding display types and interaction devices used for educational applications. Compared to desktop displays, more immersive VE systems often provide display features (e.g., stereoscopy, increased field of view) that support improved perception and understanding of spatial information. Additionally, immersive VE often allow more familiar, natural interaction methods (e.g., physical walking or rotation of the head and body) to control viewing within the virtual space. It is unknown how these features interact with the types of spatial information presentations to affect learning. The research presented in this dissertation investigates these issues in order to further the knowledge of how to design VEs to support learning. The research includes six studies (five empirical experiments and one case study) designed to investigate how spatial information presentations affect learning effectiveness and learner strategies. This investigation includes consideration for the complexity of spatial information layouts, the features of display systems that could affect the effectiveness of spatial strategies, and the degree of navigational control for accessing information. Based on the results of these studies, we created a set of design guidelines for developing VEs for learning-related activities. By considering factors of virtual information presentation, as well as those based on the display-systems, our guidelines support design decisions for both the software and hardware required for creating effective educational Ves. / Ph. D.

Deux volets distincts de l'hydrologie sont abordés, prévision et prédétermination, au travers d'une problématique commune : le transfert à l'exutoire des bassins versants d' une information hydrologique distribuée. Dans le domaine de la prévision des crues, la technologie radar procure une information pluviométrique spatialement continue. Les hydrologues disposent ainsi en temps réel de la connaissance des champs de pluie, atout indéniable pour l'anticipation des crues notamment sur des petits bassins versants par le biais de la modélisation de la pluie en débit. Dans le cadre de la méthode AIGA d'alerte crues, développée au Cemagref, une modélisation mise en oeuvre à l'échelle du pixel de pluie fournit une cartographie des contributions de débit des pixels. Dans le domaine de la prédétermination, le Cemagref a développé la méthode SHYREG qui associe un modèle régionalisé de simulation de pluies horaires à une modélisation de la pluie en débit. Une estimation statistique régionale des pluies et des débits spécifiques de différentes durées, dans une large plage de fréquence (du courant à l'exceptionnel) peut ainsi être proposée et cartographiée. L'objectif du travail présenté est d'étudier et d'élaborer des méthodologies simples de transfert de ces deux informations débitmétriques discrétisées information temps réel pour le volet prévision et information statistique pour le volet prédétermination - à l'information débit à l'exutoire du bassin versant. La méthodologie met en oeuvre des informations spatiales et une modélisation de la pluie en débit. Pour répondre à l'objectif fixé, trois axes de travail sont développés. Le premier est l'étude du comportement d'un modèle pluie-débit simple développé pour être mis en oeuvre à la maille du km². On examine en particulier s'il satisfait les caractéristiques d'invariance et de parcimonie souhaitée pour une utilisation à la fois en reconstitution de crues et en simulation. Le second axe de travail concerne l'agglomération, en prédétermination, de l'information débit statistique connue au km² pour l'estimation des quantiles de débit à l' exutoire de bassins versants de superficie plus importante dans le cadre de la méthode SHYREG. Il s'agit de tenir compte de deux phénomènes hydrologiques distincts : l'abattement spatial de la pluie et le transfert dans le réseau hydraulique. Le troisième axe de travail concerne l'agglomération de l'information hydrologique distribuée pour la reconstitution des crues dans le cadre de l'outil AIGA d'alerte crues. Différentes modélisations sont proposées pour transférer à l'exutoire les contributions des débits modélisées aux pixels. / We address the routing of distributed hydrological information to the outlet of watersheds, in the fields of flood forecasting and flood prediction on ungauged watersheds in the French Mediterranean area.Flood forecasting can benefit of areal rainfall data provided in real-time by radar networks. This data used as an input to rainfall runoff models gives access to flood anticipation on small ungauged watersheds. Within the framework of the AIGA method, developed by CEMAGREF to provide floods alert, a rainfall-runoff model is implemented at the spatial resolution of the radar data, thus providing a map of the 1 km² pixel contributions to the runoff at the catchment outlet.Flood prediction consists of assessing the frequency of occurrence of floods of different given magnitude without reference to the times at which they would occur. The SHYREG flood prediction method, developed by Cemagref associates a regionalized rainfall model with a rainfall-runoff model. It provides grids of statistical estimates of rain and runoff for various duration and return periods. Our purpose is to study and work out simple methodologies to aggregate these two gridded hydrological data - real time information for the AIGA forecasting method and statistical data for the SHYREG prediction method to the catchments outlets. Our methodology implements distributed information and a rainfall-runoff model. We have first studied the behaviour of a simple rainfall-runoff model developed to be implemented in a gridded resolution (1 km² cells) for prediction as well as for forecasting purposes. We have checked that the model parameters show no redundancy and no link with the characteristics of the rainfall events. We have then addressed the question of the aggregation of gridded hydrological data. Within the SHYREG method, it consists of assessing statistical flow estimates at catchments outlets, knowing simulated flow distributions in each cell of the catchments. This aggregation would combine two distinct hydrological phenomena: areal reduction of rainfall and discharge attenuation in the channel network. Within the AIGA method, we have focused on the routing function of the rainfall-runoff model at the 1 km² cell scale, this scale being the first step of the runoff routing from the production area to the outlet of the catchment. We have then produced streamflow hindcasts for selected observed events using different routing function, within our rainfall-runoff model.

The concept of proximity is an important aspect of human reasoning. Despite the diversity of applications that require proximity measures, the most intuitive notion is that of spatial nearness. The aim of this thesis is to investigate the underpinnings of the notion of nearness, propose suitable formalisations and apply them to the processing of GIS data. More particularly, this work offers a framework for spatial proximity that supports the development of more intuitive tools for users of geographic data processing applications. Many of the existing spatial reasoning formalisms do not account for proximity at all while others stipulate it by using natural language expressions as symbolic values. Some approaches suggest the association of spatial relations with fuzzy membership grades to be calculated for locations in a map using Euclidean distance. However, distance is not the only factor that influences nearness perception. Hence, previous work suggests that nearness should be defined from a more basic notion of influence area. I argue that this approach is flawed, and that nearness should rather be defined from a new, richer notion of impact area that takes both the nature of an object and the surrounding environment into account. A suitable notion of nearness considers the impact areas of both objects whose degree of nearness is assessed. This is opposed to the common approach of only taking one of both objects, seen as a reference to assess the nearness of the other to it, into consideration. Cognitive findings are incorporated to make the framework more relevant to the users of Geographic Information Systems (GIS) with respect to their own spatial cognition. GIS users bring a wealth of knowledge about physical space, particularly geographic space, into the processing of GIS data. This is taken into account by introducing the notion of context. Context represents either an expert in the context field or information from the context field as collated by an expert. In order to evaluate and to show the practical implications of the framework, experiments are conducted on a GIS dataset incorporating expert knowledge from the Touristic Road Travel domain.