Determining geometric primitives for a 3D GIS : easy as 1D, 2D, 3D?

Acquisition techniques such as photo modelling, using SfM-MVS algorithms, are being applied increasingly in several fields of research and render highly realistic and accurate 3D models. Nowadays, these 3D models are mainly deployed for documentation purposes. As these data generally encompass spatial data, the development of a 3D GIS would allow researchers to use these 3D models to their full extent. Such a GIS would allow a more elaborate analysis of these 3D models and thus support the comprehension of the objects that the features in the model represent. One of the first issues that has to be tackled in order to make the resulting 3D models compatible for implementation in a 3D GIS is the choice of a certain geometric primitive to spatially represent the input data. The chosen geometric primitive will not only influence the visualisation of the data, but also the way in which the data can be stored, exchanged, manipulated, queried and understood. Geometric primitives can be one-, two- and three-dimensional. By adding an extra dimension, the complexity of the data increases, but the user is allowed to understand the original situation more intuitively. This research paper tries to give an initial analysis of 1D, 2D and 3D primitives in the framework of the integration of SfM-MVS based 3D models in a 3D GIS

Spatiotemporal data as the foundation of an archaeological stratigraphy extraction and management system

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General health and residential proximity to the coast in Belgium : results from a cross-sectional health survey

The health risks of coastal areas have long been researched, but the potential benefits for health are only recently being explored. The present study compared the general health of Belgian citizens a) according to the EU's definition of coastal ( 50 km), and b) between eight more refined categories of residential proximity to the coast ( 250 km). Data was drawn from the Belgian Health Interview Survey (n = 60,939) and investigated using linear regression models and mediation analyses on several hypothesized mechanisms. Results indicated that populations living 50-100 km. Four commonly hypothesized mechanisms were considered but no indirect associations were found: scores for mental health, physical activity levels and social contacts were not higher at 0-5 km from the coast, and air pollution (PM ic , concentrations) was lower at 0-5 km from the coast but not statistically associated with better health. Results are controlled for typical variables such as age, sex, income, neighbourhood levels of green and freshwater blue space, etc. The spatial urban-rural-nature mosaic at the Belgian coast and alternative explanations are discussed. The positive associations between the ocean and human health observed in this study encourage policy makers to manage coastal areas sustainably to maintain associated public health benefits into the future

Using 3D modelling in the Valley or Turu Alty (Siberia, Russia) for research and conservational purposes

[EN] Since 1999 the Department of Archeology and the Department of Geography of Ghent University undertake field surveys to the Altai Region in Siberia, Russia. This region is a very important archaeological heritage area in the world. Scattered throughout the region are hundreds of frozen tombs, ritual monuments and petroglyphs. Research of these relics helps to understand the life of Eurasian nomads in the 4th century BC. Even more important, due to upcoming touristic activities and climate change, the documentation of the frozen tombs is imperative. A traditional archaeological survey consists out of a basic description, a drawing, one or two pictures and the GNSS location of each monument. With support of the department of Geography several topographical maps are created based on satellite images (IKONOS, Pleiades) and measurement of Ground Control Points (GCP) on site. Furthermore, since 2012 the use of 3D realistic photo modelling is being applied to survey the monuments in higher detail. The method of photo modelling proves to be successful and cost-effective. Besides their high detail, the almost real-life virtual representation of the monuments makes these techniques less abstract than a traditional archaeological survey. During the field campaigns in the summer of 2014 and 2015 this method was implied to record hundreds of monuments in the valley of Turu Alty (Siberia, Russia). Using 3D modelling software the models are created to document the monuments and petroglyphs of the study area for research and conservational purposes.Vandenbulcke, A.; Stal, C.; Lonneville, B.; Bourgeois, J.; De Wulf, A. (2016). Using 3D modelling in the Valley or Turu Alty (Siberia, Russia) for research and conservational purposes. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 408-411. https://doi.org/10.4995/arqueologica8.2015.3787OCS40841

BUILDING A VIRTUAL TIME MACHINE FOR THE ANCIENT RUINS OF JIAOHE

[EN] The goal of this work in progress is the virtual 3D reconstruction of one of the temples of the Ancient Ruins of Jiaohe (China). This site, considered as one of the key locations on the Silk Road, is slowly deteriorating due to erosion and human activity. One of its buildings, the Northwest Small Temple, was partially reconstructed as part of the Master plan for preservation and restoration as proposed by the UNESCO/Japan Trust Fund. Furthermore, a replica of the temple was built at the site entrance. The UNESCO master plan serves as the starting point for the 3D reconstruction, which is performed in three phases. The first phase comprises an initial 3D reconstruction of the temple based on floor plans and sections, and the placement of this reconstruction in a low-resolution 3D model of Jiaohe. The second phase consists of a field campaign at the site, in order to acquire the necessary data to complement the initial reconstruction: a high-resolution 3D model of the current state of the Northwest Small Temple, 3D models of the statues inside the replica of the temple and imagery of the murals inside the replica. After combining the data from phase one and two, a 3D model of the Northwest Small Temple, completed with textures and statues inside, will be placed on a 3D model of its surroundings. This final 3D model will then be made available to a broad audience as a virtual time machine, allowing the visitors to both experience the site as it is today, as the way it used to be at the peak of the site’s civilisation.Lonneville, B.; Vanhaeren, N.; Vandenbulcke, A.; De Wulf, A.; De Maeyer, P. (2016). BUILDING A VIRTUAL TIME MACHINE FOR THE ANCIENT RUINS OF JIAOHE. En 8th International congress on archaeology, computer graphics, cultural heritage and innovation. Editorial Universitat Politècnica de València. 400-403. https://doi.org/10.4995/arqueologica8.2015.3741OCS40040

Helium balloons for 3D modelling : off to a flying start?

Currently, the use of unmanned aerial vehicles (UAV) as a platform for aerial photography is becoming more and more common practice for 3D photo modelling applications. However, the use of these platforms has several drawbacks. Firstly, to recharge the UAV’s batteries a nearby electricity source is needed. This might cause problems when performing research in remote areas. Secondly, a skilled operator is required to control the UAV. Thirdly, there might be legal restrictions to the use of such an aerial platform in several countries. Finally, purchasing a UAV can form a big cost when performing a small project. To address these issues, the use of helium balloons as an alternative and low cost platform for aerial photography is proposed. To assess its efficiency, effectiveness and accuracy, several case studies are elaborated. In the first case study the accuracy of a 3D model created by laser scanning is compared with a 3D model created by helium balloon imagery (Ghent, Belgium). The second case study comprises a test of the performance of the system used at the lake of Vassivière (France). Finally, the helium balloons are deployed on the archaeological site of Edzna (Mexico). Here, a comparison is made between the accuracy of 3D models generated by UAV and helium balloon imagery. In conclusion, the advantages and drawbacks of the use of helium balloons as platform for aerial photography are listed. This allows potential users to make an informed choice between this and other platforms

Marine biodiversity discovery: the metrics of new species descriptions

Based on the World Register of Marine Species (WoRMS), there are currently c. 242,000 known valid marine species living in the world's oceans and marine biota continue to be discovered and named steadily at a current average of 2,332 new species per year. The “average” newly described marine species is a benthic crustacean, annelid, or mollusc between 2 and 10 mm in size, living in the tropics at depths of 0–60 m, and represented in the description by 7–19 specimens. It is described after a shelf life of 13.5 years in an article with two to three authors in a journal with an IF <1, published by an academic institution or society or a small commercial publisher. It is highly likely that the description is not accompanied by molecular data and that its authors do not work in an institution in a region of the world where the new species comes from. At the current pace of discovery and characterization, it will take several hundred years to describe the remaining 1–2 million unknown marine species. With increased facilitation of access to literature, marine taxonomy will increasingly rely on retired professionals and citizen scientists. The barriers to new marine species descriptions are in part technological (access to habitats that are difficult to sample) and educational (training to generate and use molecular barcodes), but mostly institutional (funding of taxonomic work) and regulatory (restrictions imposed by access and benefit sharing legislation)

Exploring hypotheses on karez initiation and decline in the Flaming Mountains from a photo modelling campaign

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