On Spatial Database Integration

This paper investigates the problems that arise when application requirements command that autonomous spatial databases be integrated into a federated one. The paper focuses on the most critical issues raised by the integration of databases of different scales. A short presentation of approaches to interoperability and of the main steps composing the integration process is given first. Next, a general format is proposed for precisely defining correspondences between objects of two databases. The format can deal with a wide range of discrepancies in GIS data. Last, a solution is presented for aggregation conflicts which arise when one object of one database corresponds to a set of objects in the other database, a very frequent case when the databases are of different scales. The method is applied to excerpts of real cartographic databases

Supporting Distributed Geo-Processing: A Framework for Managing Multi-Accuracy Spatial Data

Negli ultimi anni molti paesi hanno sviluppato un'infrastruttura tecnologica al fine di gestire i propri dati geografici (Spatial Data Infrastructure, SDI). Tali infrastrutture rechiedono nuove ed efficati metodologie per integrare continuamente dati che provengoono da sorgenti diverse e sono caratterizzati da diversi livelli di qualit\ue0. Questo bisogno \ue8 riconosciuto in letteratura ed \ue8 noto come problema di integrazione del dato (data integration) o fusione di informazioni (information fusion). Un aspetto peculiare dell'integrazione del dato geografico riguarda il matching e l'allineamento degli oggetti geometrici. I metodi esistenti solitamente eseguono l'integrazione semplicemente allineando il database meno accurato con quello pi\uf9 accurato, assumendo che il secondo contenga sempre una rappresentazione migliore delle geometrie rilevate. Seguendo questo approccio, gli oggetti geografici sono combinati assieme in una maniera non ottimale, causando distorsioni che potenzialmente riducono la qualit\ue0 complessiva del database finale. Questa tesi si occupa del problema dell'integrazione del dato spaziale all'interno di una SDI fortemente strutturata, in cui i membri hanno preventivamente aderito ad uno schema globale comune, pertanto si focalizza sul problema dell'integrazione geometrica, assumendo che precedenti operazioni di integrazione sullo schema siano gi\ue0 state eseguire. In particulare, la tesi inizia proponendo un modello per la rappresentazione dell'informazione spaziale caratterizzata da differenti livelli di qualit\ue0, quindi definisce un processo di integrazione che tiene conto dell'accuratezza delle posizioni contenute in entrambi i database coinvoilti. La tecnica di integrazione proposta rappresenta la base per un framework capace di supportare il processamento distributo di dati geografici (geo-processing) nel contesto di una SDI. Il problema di implementare tale computazione distribuita e di lunga durata \ue8 trattato anche da un punto di vista pratico attraverso la valutazione dell'applicabilit\ue0 delle tecnologie di workflow esistenti. Tale valutazione ha portato alla definizione di una soluzione software ideale, le cui caratteristiche sono discusse negli ultimi capitoli, considerando come caso di studio il design del processo di integrazione proposto.In the last years many countries have developed a Spatial Data Infrastructure (SDI) to manage their geographical information. Large SDIs require new effective techniques to continuously integrate spatial data coming from different sources and characterized by different quality levels. This need is recognized in the scientific literature and is known as data integration or information fusion problem. A specific aspect of spatial data integration concerns the matching and alignment of object geometries. Existing methods mainly perform the integration by simply aligning the less accurate database with the more accurate one, assuming that the latter always contains a better representation of the relevant geometries. Following this approach, spatial entities are merged together in a sub-optimal manner, causing distortions that potentially reduce the overall database quality. This thesis deals with the problem of spatial data integration in a highly-coupled SDI where members have already adhered to a common global schema, hence it focuses on the geometric integration problem assuming that some schema matching operations have already been performed. In particular, the thesis initially proposes a model for representing spatial data together with their quality characteristics, producing a multi-accuracy spatial database, then it defines a novel integration process that takes care of the different positional accuracies of the involved source databases. The main goal of such process is to preserve coherence and consistency of the integrated data and when possible enhancing its accuracy. The proposed multi-accuracy spatial data model and the related integration technique represent the basis for a framework able to support distributed geo-processing in a SDI context. The problem of implementing such long-running distributed computations is also treated from a practical perspective by evaluating the applicability of existing workflow technologies. This evaluation leads to the definition of an ideal software solution, whose characteristics are discussed in the last chapters by considering the design of the proposed integration process as a motivating example

A Rule Based System for Assisting the Spatial Adjustment Process

This thesis describes a set of rules for control point matching between an original and an upgraded cadastre. The application of these rules results in the creation of shift vectors or links. The links can be supplied to any suitable spatial adjustment algorithm to adjust map layers captured from an old cadastre, for example, census blocks, to bring them into line with an upgraded cadastre. The solution requires no user supplied search-distance parameters

Implementing an Agro-Environmental Information System (AEIS) Based on GIS, Remote Sensing, and Modelling -- A case study for rice in the Sanjiang Plain, NE-China

Information on agro-ecosystems is crucial for understanding the agricultural production and its impacts on the environment, especially over large agricultural areas. The Sanjiang Plain (SJP), covering an area of 108 829 km², is a critical food base located in NE-China. Rice, soya bean and maize are the major crops in the SJP which are sold as commercial grain throughout China. The aim of this study is to set up an Agro-Environmental Information System (AEIS) for the SJP by employing the technologies of geographic information systems (GIS), remote sensing (RS), and agro-ecosystem modelling. As the starting step, data carrying interdisciplinary information from multiple sources are organized and processed. For an AEIS, geospatial data have to be acquired, organized, operated, and even regenerated with good positioning conditions. Georeferencing of the multi-source data is mandatory. In this thesis, high spatial accuracy TerraSAR-X imagery was used as a reference for georeferencing raster satellite data and vector GIS topographic data. For the second step, the georeferenced multi-source data with high spatial accuracy were integrated and categorized using a knowledge-based classifier. Rice was analysed as an example crop. A rice area map was delineated based on a time series of three high resolution FORMOSAT-2 (FS-2) images and field observed GIS topographic data. Information on rice characteristics (i.e., biomass, leaf area index, plant nitrogen concentration and plant nitrogen uptake) was derived from the multi-temporal FS-2 images. Spatial variability of rice growing status on a within-field level was well detected. As the core part of the AEIS, an agro-ecosystem modelling was then applied and subsequently crops and the environmental factors (e.g., climate, soil, field management) are linked together through a series of biochemical functions inherent in the modelling. Consequently, the interactions between agriculture and the environment are better interpreted. In the AEIS for the SJP, the site-specific mode of the DeNitrification-DeComposition (DNDC) model was adapted on regional scales by a technical improvement for the source code. By running for each pixel of the model input raster files, the regional model assimilates raster data as model inputs automatically. In this study, detailed soil data, as well as the accurate field management data in terms of crop cultivation area (i.e. rice) were used as model inputs to drive the regional model. Based on the scenario optimized from field observation, rice yields over the Qixing Farm were estimated and the spatial variability was well detected. For comparison, rice yields were derived from multi-temporal FS-2 images and the spatial patterns were analysed. As representative environmental effects, greenhouse gas of nitrous oxide (N2O) and carbon dioxide (CO2) emitted from the paddy rice fields were estimated by the regional model. This research demonstrated that the AEIS is effective in providing information about (i) agriculture on the region, (ii) the impacts of agricultural practices on the environment, and (iii) simulation scenarios for sustainable strategies, especially for the regional areas (e.g. the SJP) that is lacking of geospatial data

Digital photogrammetry for visualisation in architecture and archaeology

Bibliography: leaves 117-125.The task of recording our physical heritage is of significant importance: our past cannot be divorced from the present and it plays an integral part in the shaping of our future. This applies not only to structures that are hundreds of years old, but relatively more recent architectural structures also require adequate documentation if they are to be preserved for future generations. In recording such structures, the traditional 2D methods are proving inadequate. It will be beneficial to conservationists, archaeologists, researchers, historians and students alike if accurate and extensive digital 3D models of archaeological structures can be generated. This thesis investigates a method of creating such models, using digital photogrammetry. Three different types of model were generated: 1. the simple CAD (Computer Aided Design) model; 2. an amalgamation of 3D line drawings; and 3. an accurate surface model of the building using DSMs (Digital Surface Models) and orthophotos

Modeling and improving Spatial Data Infrastructure (SDI)

Spatial Data Infrastructure (SDI) development is widely known to be a challenging process owing to its complex and dynamic nature. Although great effort has been made to conceptually explain the complexity and dynamics of SDIs, few studies thus far have actually modeled these complexities. In fact, better modeling of SDI complexities will lead to more reliable plans for its development. A state-of-the-art simulation model of SDI development, hereafter referred to as SMSDI, was created by using the system dynamics (SD) technique. The SMSDI enables policy-makers to test various investment scenarios in different aspects of SDI and helps them to determine the optimum policy for further development of an SDI. This thesis begins with adaption of the SMSDI to a new case study in Tanzania by using the community of participant concept, and further development of the model is performed by using fuzzy logic. It is argued that the techniques and models proposed in this part of the study enable SDI planning to be conducted in a more reliable manner, which facilitates receiving the support of stakeholders for the development of SDI.Developing a collaborative platform such as SDI would highlight the differences among stakeholders including the heterogeneous data they produce and share. This makes the reuse of spatial data difficult mainly because the shared data need to be integrated with other datasets and used in applications that differ from those originally produced for. The integration of authoritative data and Volunteered Geographic Information (VGI), which has a lower level structure and production standards, is a new, challenging area. The second part of this study focuses on proposing techniques to improve the matching and integration of spatial datasets. It is shown that the proposed solutions, which are based on pattern recognition and ontology, can considerably improve the integration of spatial data in SDIs and enable the reuse or multipurpose usage of available data resources

Detection and elimination of rock face vegetation from terrestrial LIDAR data using the virtual articulating conical probe algorithm

A common use of terrestrial lidar is to conduct studies involving change detection of natural or engineered surfaces. Change detection involves many technical steps beyond the initial data acquisition: data structuring, registration, and elimination of data artifacts such as parallax errors, near-field obstructions, and vegetation. Of these, vegetation detection and elimination with terrestrial lidar scanning (TLS) presents a completely different set of issues when compared to vegetation elimination from aerial lidar scanning (ALS). With ALS, the ground footprint of the lidar laser beam is very large, and the data acquisition hardware supports multi-return waveforms. Also, the underlying surface topography is relatively smooth compared to the overlying vegetation which has a high spatial frequency. On the other hand, with most TLS systems, the width of the lidar laser beam is very small, and the data acquisition hardware supports only first-return signals. For the case where vegetation is covering a rock face, the underlying rock surface is not smooth because rock joints and sharp block edges have a high spatial frequency very similar to the overlying vegetation. Traditional ALS approaches to eliminate vegetation take advantage of the contrast in spatial frequency between the underlying ground surface and the overlying vegetation. When the ALS approach is used on vegetated rock faces, the algorithm, as expected, eliminates the vegetation, but also digitally erodes the sharp corners of the underlying rock. A new method that analyzes the slope of a surface along with relative depth and contiguity information is proposed as a way of differentiating high spatial frequency vegetative cover from similar high spatial frequency rock surfaces. This method, named the Virtual Articulating Conical Probe (VACP) algorithm, offers a solution for detection and elimination of rock face vegetation from TLS point cloud data while not affecting the geometry of the underlying rock surface. Such a tool could prove invaluable to the geotechnical engineer for quantifying rates of vertical-face rock loss that impact civil infrastructure safety --Abstract, page iii

Development and characterization of novel nanobiocomposites containing various nanofillers to improve barrier and other physical properties of interest in food packaging and coating applications

The development of novel biobased materials with tailored properties for food biopackaging applications is a topic of significant interest within academic and industrial laboratories. The current PhD thesis deals with the development and characterization of novel biocomposites and nanobiocomposites of biopolyesters, polysaccharides and proteins containing different micro and nanoadditives. The main aim of the work was to provide novel solutions, making use to the extent possible of natural additives, to enhance the gas and vapour barrier properties of the various biopolymers while retaining the good properties of the matrix and even adding novel functionalities such as antimicrobial character. The transport of low molecular weitght compounds through polymeric materials, i.e. the so-called barrier properties, is known to be a significant limiting factor for the widespread application of biopolymers in packaging, coating and membrane applications. To that end, different micro and nanobiocomposites were formulated which contained as reinforcing elements food contact complying nanoclays, amylopectin, natural extracts, carbon nanofibers and nanotubes, cellulose microfibers and cellulose nanowhiskers. From the work novel biocomposites were developed which exhibited enhanced gas, vapour and UV light barrier and which simultaneously were able to provide controlled release of natural antimicrobials. These new property balanced composites can have significant potential in the design of novel biopackaging and biocoating materials.Sánchez García, MD. (2011). Development and characterization of novel nanobiocomposites containing various nanofillers to improve barrier and other physical properties of interest in food packaging and coating applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/10361Palanci

Signifikanz von Sidescan Sonar Daten für morphodynamische Untersuchungen in Schelf-Meeren : Fallstudien anhand von Unterwasser-Dünen Wanderung, Verfüllung von Entnahmegruben und Stabilität sortierter Bodenformen

A side-looking sonar was constructed for military purposes during World War II as a development of forward-search sonars used for detection of foe submarines hiding motionless on a seabed. An unexpected career of sidescan sonars began with their implementation in marine geology. A sonar ability to recognise sediment roughness and consequently grain size allowed significant opportunities for sediment mapping, which were spatially more precise than the ones performed by sediment sampling. In addition, an acoustic shadow caused by close-seabed scanning over troughs and ridges allowed easier interpretation of the bottom morphology. These revolutionary features opened new ways of underwater exploration. Some multi-disciplinary applications of sonographs on continental shelves are presented in the introduction of this work after a technical description of a sidescan sonar system, and sonograph processing issues. The main objective of this work is to discuss three case studies on sidescan sonar applications in seabed dynamics research. Each of the study was constructed as a separate research paper qualified for prestigious journals and thus, the introductory part of this work is a descriptive supplement of information enclosed in the presented manuscripts. A case study from the southern Vietnamese shelf is focused on sand dunes mapping on the basis of not mosaicked sonographs. It was the first investigation on bedforms from this area; however it contains data only from the end of the winter monsoon. The shelf area was divided into five zones grouping dunes of similar size, shape and orientation. All located sand dunes higher than 1.5 m were described, summarized in a scatter plot of height/length ratio and thus compared to dunes observed on other shelves. The dunes orientation corresponded to the overall South China Sea circulation pattern during the winter monsoon. Therefore, the possibility of dunes mobilisation was investigated with the help of empirical equations predicting sediment transport. Depth-integrated velocities necessary to put sediment forming dunes in motion were calculated for distinguished zones. The results were discussed with hydrodynamic in-situ measurements of other authors and it was concluded that most of the investigated dunes were likely to migrate actively following the monsoon circulation. A case study from the Baltic Sea is a rare example of an investigation focused on changes in the morphology of pits created by anchor hopper dredging of marine sand and gravel aggregates. By means of sidescan sonar and multi-beam echosounder data, a six-year evolution of four pits was presented. In the case of three pits dredged in a sandy seabed faster smoothing of edges and infilling rates larger than in the case of a pit dredged in gravel were clearly observed. The edges of the gravel pit were expanding due to collapsing of the side-walls. The infilling of the pit was investigated based on approximations of pit depth by single- and multi-beam echosoundings, as well as acoustic shade length in the sonographs. Earlier studies of other authors on this pit allowed plotting a curve of infilling rate over six years of pit evolution. The filling clearly slowed down over time and the reasons for that are discussed in this paper. The sand screened in the dredging process surrounded the investigated pit and its backscatter values in sonographs clearly separate it from the gravel seabed. The area covered by the screened sand fraction was monitored and appeared to be decreasing in time. Hydrological data showed the possibility of frequent mobilisation of this fraction and therefore indicated it as the main source for pit infilling. A case study from the North Sea presents a unique approach of conversion analogue sidescan sonar data into digital, geo-referenced form in order to present morphological stability and birth of sorted bedforms. The analogue mosaic was geo-coded in a DECCA navigation system in 1977. DECCA system technology was described thoroughly and a study of the spatial errors was presented for accurate geo-referencing of the mosaic. Image warping by rubber-sheeting method was performed to compare old sonographs of a sorted bedform with sonographs from 2002. A continuation study of Dr. Markus Diesing et al. additionally contains a multi-beam backscatter mosaic from 2003 as a comparison data-set. The morphological stability of the bedforms over time was discussed in the paper and compared to worldwide examples. Hydrodynamic conditions influencing the bedforms were presented and a significant role of the tidal currents in shaping the sorted bedforms was demonstrated. An asymmetry of a newly appeared sorted bedform, however, was probably related rather to high energy storm events. Even though the sidescan sonar data were collected from three different seas for three different case studies in three different scales, sonographs proved to be a valuable tool in each of the cases. Minor limitations of sidescan sonar systems and options for applying other devices for the same types of investigations are discussed in the end of this work.Während des Zweiten Weltkrieges wurde für militärische Zwecke zum Aufspüren feindlicher Unterseeboote, die die sich bewegungslos auf dem Meeresgrund versteckten, ein seitwärts schauendes Sonar als Fortentwicklung des vorwärts schauenden Sonars gebaut. Eine unerwartete Karriere dieses Seitensicht-Sonars begann mit seiner Einführung in der Marinen Geologie. Die Fähigkeit des Sonars, die Sedimentrauhigkeit und infolgedessen die Korngröße zu erkennen, eröffnete bedeutende Möglichkeiten in der Sedimentkartierung mit einer räumlich besseren Auflösung als sie durch Probennahmen zu erreichen ist. Zusätzlich erlaubt ein akustischer Schatten, der durch bodennahes Überfahren von Vertiefungen und Erhebungen verursacht wird, eine einfachere Interpretation der Morphologie des Meeresgrundes. Diese revolutionären Eigenschaften öffneten neue Wege der Unterwassererforschung. Einige multidisziplinäre Anwendungen von Sonographen auf Kontinentalsockeln werden in der Einleitung zu dieser Arbeit neben technischen Besonderheiten des Seitensicht-Sonar-Systems und Implikationen bei der Verarbeitung von Sonographie-Daten beschrieben. Die Hauptzielsetzung dieser Arbeit ist es, drei Fallstudien der Anwendung eines Seitensicht-Sonars in Meeresgrunddynamikstudien darzustellen. Jede der Studien wurde für anerkannte Journale verfasst oder angenommen, der einleitende Teil dieser Arbeit ist eine beschreibende Ergänzung der Informationen in den vorgestellten Veröffentlichungen. Eine Fallstudie am Südvietnamesischen Kontinentalsockel ist auf die Kartierung der Sanddünen auf der Basis nicht zusammengesetzter Sonographie-Daten ausgerichtet. Es ist die erste Untersuchung von Bodenformen in diesem Gebiet, enthält jedoch nur Daten vom Ende des Wintermonsuns. Der Schelfbereich wurde in fünf Zonen eingeteilt, um Dünen ähnlicher Größe, Form und Orientierung zu gruppieren. Alle lokalisierten Sanddünen mit einer Höhe größer als 1.5 m wurden beschrieben und in ihrem höhen/längen Verhältnis in einem Scatterplot dargestellt, und auf diese Weise mit Dünen auf anderen Schelfen verglichen. Die Düneorientierung entspricht dem allgemeinen Zirkulationsschema der Südchinesischen See während des Wintermonsuns. Die Möglichkeit der Dünenmobilisierung wurde mit Hilfe empirischer Sedimenttransportgleichungen untersucht. Tiefengemittelte Strömungs­geschwindigkeiten, notwendig um Sedimente zur Bildung von Dünen in Bewegung zu setzen wurden berechnet. Die errechneten Ergebnisse wurden mit hydrodynamischen In-Situ Messungen anderer Autoren verglichen und es wurde gefolgert, dass die meisten untersuchten Dünen aktiv entsprechend der Monsunzirkulation wandern. Eine Fallstudie in der Ostsee ist ein seltenes Beispiel einer Untersuchung von Änderungen in der Morphologie von Gruben, die durch Nassbaggern von Marinen Sanden und Kiesen entstandenen sind. Mittels Seitensicht-Sonar und Fächerecholot-Daten wurde die Entwicklung von vier Gruben über sechs Jahre dargestellt. Im Falle dreier Gruben in sandigem Untergrund konnte eine deutlich höhere Abrundungsrate der Kanten und Sedimentation in den Gruben beobachtet werden als dies bei der Grube im Kiesbett der Fall war. Die Ränder der Grube im Kies änderten sich durch Abrutschen der Seitenwände. Sedimentation in den Gruben wurde basierend auf Näherungswerten der Grubetiefe durch Single-Beam-Echolot und Fächerecholot-Messungen, sowie akustische Schattenlänge in den Sonographie-Daten untersucht. Frühere Studien anderer Autoren an diesen Gruben ermöglichten es, die Sedimentationsrate über sechs Jahre darzustellen. Die Sedimentationsrate verlangsamte sich mit der Zeit deutlich, die Gründe hierfür werden in diesem Paper dargestellt. Der Sand, der während des Nassbaggerns ausgesiebt wurde, konnte im Umkreis der untersuchten Grube nachgewiesen werden, das Echo in den Sonographie-Daten war deutlich von dem des kiesigen Meeresgrundes zu unterscheiden. Der Bereich, der durch die ausgesiebte Sandfraktion bedeckt wurde, wurde beobachtet und verringerte sich mit der Zeit. Hydrologische Daten zeigen die Möglichkeit einer häufigen Mobilisierung dieser Sandfraktion, wodurch diese als hauptsächliche verantwortliche Quelle für die Sedimentation in den Gruben ausgemacht werden kann. Eine Fallstudie in der Nordsee stellt einen einmaligen Ansatz der Umwandlung von analogen Seitensicht-Sonar-Daten in digitale, georeferenzierte Form dar, um die morphologische Stabilität und die Entstehung von sortierten Bodenformen darzustellen. Das analoge Mosaik wurde 1977 im DECCA Navigationssystem geo-kodiert. Die DECCA System Technologie wurde gänzlich beschrieben und für die genaue Georeferenzierung des Mosaiks wurde eine Studie der räumlichen Fehler präsentiert. Eine Anpassung des Bildes wurde per “rubber – sheeting“ Methode durchgeführt um historische Sonographie-Daten sortierter Bodenformen mit neuen Sonographie-Daten von 2002 zu vergleichen. Eine nachfolgende Studie von Dr. Markus Diesing et al. enthält zusätzlich ein “multi-beam backscattering“ Mosaik von 2003 als vergleichendes Material. Die morphologische Stabilität der Bodenformen über die Zeit wird in dem Paper besprochen und mit weltweiten Beispielen verglichen. Die hydrodynamischen Umgebungsbedingungen der Bodenformen wurden dargestellt und eine bedeutende Rolle der Gezeiten-Strömungen auf diese festgestellt. Eine Asymmetrie neu entstandener sortierter Bodenformen hing vermutlich mit Sturmereignissen hoher Energie zusammen. Obwohl die Seitensicht-Sonar-Daten in drei unterschiedlichen Meeren für drei unterschiedliche Untersuchungen und in drei unterschiedlichen Maßstäben gesammelt wurden, waren die Sonographie-Daten in jedem der Fälle ein wertvolles Hilfsmittel. Die kleineren Beschränkungen von Seitensicht-Sonar-Systemen und die Möglichkeit der Anwendung anderer Systemen für die gleichen Studien werden im Ende dieser Arbeit diskutiert