The need for accurate registration of underground objects in the 3D cadastre is becoming increasingly common throughout the world. Research studies conducted in this area mostly focus on objects related to transportation or other public utilities and services. However, in settlements with a long history, apart from new objects, there are also various historical objects underground. Such places are not fully discovered, and sometimes they are not even fully inventoried with surveying methods. The aim of this work therefore is to try to describe the possibility of introducing historical undergrounds to the real estate cadastre created for three dimensions, in case of its creation, and to check ground laser scanning as a method of measuring such objects in order to introduce them to the 3D cadastre. Considerations on the inclusion of underground historical objects into the three-dimensional cadastre database began with conceptual considerations. Their result is the elaboration of UML schemas describing relationships among 3D cadastre objects including underground objects. According to the authors, such underground objects should constitute a completely new class called ‘EGB_BuildingBlockUnderground3D’ and be part of the legal space of the entire building represented by the class ‘EGB_BuildingLegalSpace3D’ (the prefix EGB is an acronym of Polish cadastre name ‘Ewidencja Gruntów i Budynków’; in English, it stands for ‘Land and Building Cadastre’). In order to verify in practice the possibility of introducing historical underground objects into the 3D cadastre database, the inventory of the Underground Tourist Route in Rzeszów (Poland) was used. This route consists of a network of underground passageways and cellars built between the 14th and 18th centuries. The measurement was carried out with the application of the Faro Focus 3D terrestrial laser scanner. The underground inventory showed that at the time the current cadastre of land and buildings in Rzeszów was being founded, the boundaries of the cadastral parcels were established without knowing the location of the underground passageways under the Main Market Square. This resulted in a situation in which the objects located underground became parts of more than one cadastral parcel. If a 3D cadastre is created, such a situation must of course be recorded accordingly. The article proposes solutions for such situations.
Industry Foundation Classes (IFC), the buildingSMART open standard for BIM, is underused with respect to its promising potential, since, according to the experience of practitioners and researchers working with BIM, issues in the standard's implementation and use prevent its effective use. Nevertheless, a systematic investigation of these issues has never been carried out, and there is thus insufficient evidence for tackling the problems. The GeoBIM benchmark project is aimed at finding such evidence by involving external volunteers, reporting onin parallel, also with the aim of understanding whether one of the two offered more effective solutions that could possibly be borrowed by the other one in future developments. However, the final outcomes of the two different tasks are very specific for each standard and deserve to be presented and discussed separately, considering the specifics of each case. For these reasons, this article, which focuses on the results about the benchmark Task 1 (support for IFC), is written in tandem with Noardo et al. (2020c), which describes Task 3, covering the support for CityGML. In order to allow each article to be read on its own, the two articles share some information (i.e., Section 2 explaining the general context and motivation of the study; Section 3. 1 covering the initial part of the methodology about the entire GeoBIM benchmark set-up, and Section 3. 3 concerning some similarities in the methodology). One further article explores the parts of the project more directly related to the subject of integration, namely, conversion procedures and useful tools to georeference IFC models .
<p><strong>Abstract.</strong> LiDAR technology has revolutionized the area of 3D data acquisition. It is possible to obtain in a very fast and accurate way geometric and other information for a large area . Along with the development of design technology, LiDAR point clouds are often used to create inventory models of building objects and installations. This paper presents the possibilities of assessing LiDAR data for BIM modeling. The areas in which the assessment and description of obtained TLS data is important are presented. In addition to the attributes for assessing the quality of spatial data contained in the ISO 19157 standard, a density parameter was proposed. Examples of point clouds with different density for the architectural detail are presented in the final part of the work. For the attributes describing LiDAR data sets the levels of importance have been proposed for.</p>
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