1,720,952 research outputs found
Standaarden voor 3D geo-informatie
No full textStandaarden voor het beheer, de modellering, uitwisseling en ontsluiting van 3D informatie zijn essentieel bij 3D ontwikkelingen: standaarden voor 3D data bieden softwarebedrijven een solide basis voor investeringen. Bovendien maken 3D standaarden hergebruik van 3D data mogelijk
Footprint decomposition combined with point cloud segmentation for producing valid 3D models
No full textFor the creation of three-dimensional (3D) city models, extrusion of building footprints is widely applied. Extrusion results in block shaped buildings. The main problem with these 3D models is that they do not represent height differences within a building. This thesis presents a method to improve building footprints by subdivision into parts describing height differences and roof shapes. These improved building footprints are used for creating 3D models by separate extrusion of each of these parts. Applying this method results in 3D building models with multiple heights. Several subjects are discussed in this thesis: generalization, decomposition, segmentation, 3D geometry reconstruction and their validation. This research is based on the combination of two existing methods, one for generalization and decomposition of building footprints, and one for segmentation of point clouds. These methods are extended and problems are solved by including: (1) direction of lines, (2) best fitting line, (3) adjacent buildings, (4) preservation of holes, (5) handling of slant lines, (6) quality statistics and (7) validation. The existing generalization method creates topology errors which are reduced by including knowledge from adjacent buildings. Decomposed building footprints are merged based on the segmented point cloud. The resulting decomposition is a subdivision describing multiple roof shapes and height jumps, based on linear features in the building footprint. Reconstruction of the actual 3D geometry is performed by extrusion of the decomposition cells. The resulting reconstruction is a Level of Detail 1 (LoD) model with height differences. To test the usability of the improved footprints for reconstruction of a LoD2 model, parametric shape fitting is applied. These tests are executed using a small set of roof shapes proving the usability. All reconstructed 3D building geometries are validated using Oracle Spatial 11g. In order to analyze, test and improve the developed algorithms, a prototype is implemented in C++. This prototype is tested intensively with several real-world data sets. Results from these tests are proving proper functioning of the developed method and support the conclusions.GeomaticsGIS TechnologyOTB Research Institute for the Built Environmen
3D BGT: waarom, wat en hoe?
No full textEr zijn veel thema’s in de Omgevingswet die een 3D-component hebben. Er is dan ook een groeiende vraag om 3D geo-informatie in het DSO (Digitaal Stelsel Omgevingswet) te faciliteren. Een goede basis hiervoor is 3D BGT. IMGeo, het informatiemodel dat de inhoud van de Basisregistratie Grootschalige Topografie (BGT) vastlegt, is voorbereid op 3D en zou daarmee een basis kunnen zijn voor deze 3D informatiebehoefte. Hoe werkt de implementatie van 3D IMGeo in de huidige praktijk? Is de 2D BGT, nu deze bijna landsdekkend beschikbaar is, eenvoudig uit te breiden naar 3D? Zijn de 3D IMGeo specificaties eenduidig en geschikt voor 3D-toepassingen? En hoe kan een 3D-versie van de BGT worden geïmplementeerd inclusief beheer en ontsluiting?Urban Data Scienc
Measure the climate, model the city
No full textModern large cities are characterized by a high building concentration, little aeration and lack of green spaces. Such characteristics create an urban climate which is different from the climate outside of cities. An example of an urban climate effect is the so-called Urban Heat Island: cities tend to be warmer than the surrounding rural areas. The higher temperature results in an increase in energy consumption since people, especially in summer, use artificial means to cool themselves. Although means of mitigating the UHI effect exist, they are difficult to justify, as knowledge about urban climate is limited, and analysis tools are lacking. This paper presents the work carried during the 2010 MSc Geomatics Synthesis Project. A 3D spatial relational database has been implemented which is meant to act as starting point in the development of a 3D climate-enabled geographical information system. To this end, the database stores 3D geometries representing the built environment and its thematic properties. The database is also able to store measurements of climate parameters, in this case temperature, obtained through mobile sensors. Spatial analyses and queries are supported, allowing users to calculate areas, distances, buffers, add and remove geometries and thematic attributes. The database design is based on the CityGML information model which has been extended to allow the storage of climate parameters relevant to urban climate research.OTB ResearchOTB Research Institute for the Built Environmen
3D-inputgegevens voor geluidssimulaties gegenereerd uit bestaande landsdekkende datasets
No full textGeluid is een groot probleem in stedelijk gebied. Om geluidsoverlast te verminderen, voeren vele overheidsorganisaties op allerlei niveaus geluidstudies uit. Geluidssimulatie is hierin een belangrijk onderdeel. De reken methode voor de simulatie van geluid is in Nederland gestandaardiseerd. Maar de benodigde 3D-inputgegevens worden voor iedere geluidstudie opnieuw gecreëerd. Dit is niet efficiënt, maar evenzo belangrijk is dat verschillen in inputgegevens kunnen leiden tot verschillen in de uitkomsten. Daarom bekijken we in een samenwerking van RIVM, Rijkswaterstaat, het Kadaster, IPO en de TU Delft hoe de benodigde inputgegevens over de fysieke ruimte automatisch kunnen worden gegenereerd uit landsdekkende gegevensbronnen zoals de BGT, de BAG en het AHN en voor overheden beschikbaar kan worden gesteld.Urban Data Scienc
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Automated reconstruction of 3D input data for noise simulation.
No full textNoise is one of the main problems in urban areas. To monitor and manage noise problems, governmental organisations at all levels are obliged to regularly carry out noise studies. The simulation of noise is an important part of these studies. Currently, different organisations collect their own 3D input data as required in noise simulation in a semi-automated way, even if areas overlap. This is not efficient, but also differences in input data may lead to differences in the results of noise simulation which has a negative impact on the reliability of noise studies. To address this problem, this paper presents a methodology to automatically generate 3D input data as required in noise simulations (i.e. buildings, terrain, land coverage, bridges and noise barriers) from current 2D topographic data and point clouds. The generated data can directly be used in existing noise simulation software. A test with the generated data shows that the results of noise simulation obtained from our generated data are comparable to results obtained in a current noise study from practice. Automatically generated input data for noise simulation, as achieved in this paper, can be considered as a major step in noise studies. It does not only significantly improve the efficiency of noise studies, thus reducing their costs, but also assures consistency between different studies and therefore it improves the reliability and reproducibility. In addition, the availability of countrywide, standardised input data can help to advance noise simulation methods since the calculation method can be adopted to improved ways of 3D data acquisition and reconstruction.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Urban Data Scienc
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