Diachronic Reconstruction and Visualization of Lost Cultural Heritage Sites

25 p.Cultural heritage (CH) documentation is essential for the study and promotion of CH assets/sites, and provides a way of transmitting knowledge about heritage to future generations. The integration of the fourth dimension into geospatial datasets enables generating a diachronic model of CH elements, namely, a set of three-dimensional (3D) models to represent their evolution in various historical phases. The enhanced four-dimensional (4D) modeling (3D plus time) pursues a better understanding of the CH scenario, enriching historical hypotheses as well as contributing to the conservation and decision-making process. Although new geomatic techniques have reduced the amount of fieldwork, when put together, the geometric and temporal dimensions imply the interpretation of heterogeneous historical information sources and their integration. However, this situation could reach a critical point when the study elements are no longer present. The main challenge is to harmonize the different historical and archaeological data sources that are available with the current remains in order to graphically rebuild and model the lost CH assets with a high degree of reliability. Moreover, 4D web visualization is a great way to disclose the CH information and cultural identity. Additionally, it will serve as a basis to perform simulations of possible future risks or changes that can happen during planned or hypothetical restoration processes. This paper aims to examine the study case of a diachronic reconstruction by means of a mobile laser system (MLS) and reverse modeling techniques for a lost urban CH element: the citadel or Alcázar gate of Ávila. Within this aim, the final model is evaluated in terms of the consistency of the historical sources to assess its suitability considering the constructive interpretations that are required to integrate heterogenous data sources. Moreover, geometric modeling is evaluated regarding the current remains and its surroundings. Finally, a web 4D viewer is presented for its dissemination and publicity. This paper is an extended and improved version of our paper that was published in the 2018 ISPRS Technical Commission II Symposium, Riva del Garda, Italy, 3–7 June 2018.S

FROM ARCHIVE DOCUMENTATION TO ONLINE 3D MODEL VISUALIZATION OF NO LONGER EXISTING STRUCTURES: THE TURIN 1911 PROJECT

Rebuilding the past of cultural heritage through digitization, archiving and visualization by means of digital technology is becoming an emerging issue to ensure the transmission of physical and digital documentation to future generations as evidence of culture, but also to enable present generation to enlarge, facilitate and cross relate data and information in new ways. In this global effort, the digital 3D documentation of no longer existing cultural heritage can be essential for the understanding of past events and nowadays, various digital techniques and tools are developing for multiple purposes. In the present research the entire workflow, starting from archive documentation collection and digitization to the 3D models metrically controlled creation and online sharing, is considered. The technical issues to obtain a detail 3D model are examined stressing limits and potentiality of 3D reconstruction of disappeared heritage and its visualization exploiting three complexes belonging to 1911 Turin World’s Fair

On the Use of Historical Flights for the Urban Growth Analysis of Cities Through Time: The Case Study of Avila (Spain)

17 p.Historical aerial images are a unique and relatively unexplored means of deriving spatio-temporal information for scenes and landscapes. Such historical imagery can be combined with photointerpretation and image-based 3D modelling techniques, providing the fourth dimension of time to 3D geometrical representations. This allows urban planners, historians, and other specialists to identify, describe, and analyse changes in scenes and landscapes. Urban growth has an important impact on the sustainable development of cities. An important step for the analysis of urban growth is the identification of different urban sectors. To this end, this paper proposes a methodology for the 4D urban growth analysis of cities through time using a free and open source software developed by the authors. This approach uses the latest advances in photogrammetry, including the so-called incremental Structure from Motion, to evaluate the urbanistic changes of a city by means of confronting two-point clouds from different eras. The objectives of this paper are twofold: (i) first, the processing of historical aerial images using modern photogrammetric techniques; (ii) second, deriving spatio-temporal information for urban cities, offering a method for researchers to identify changes over time. In order to validate this method, the urban growth of the city of Avila between 1956 and 2017 was assessed taking the historical American flight of 1956 and the digital aerial flight of 2017. The results were statistically assessed according to georeferencing quality, confirming that the approach developed can be used to support urban growth analysis through time and providing relevant data in 2D and 3DS

Lost landscapes of mountain agriculture of Šumava (Bohemian Forest): reconstruction, 3D models of landscape and possibilities of their presentation on web

Práce se zabývá modelovým územím obce Prášily na Šumavě, které je analyzováno v rámci projektu Dědictví zaniklých krajin, identifikace, rekonstrukce a zpřístupnění. Cílem práce bylo zhodnotit změny krajinného pokryvu od poloviny 19. století do současnosti s využitím stabilního katastru, historického ortofota, současného ortofota a vytvoření rekonstrukčních 3D modelů krajiny a fotorealistického 3D modelu zaniklé osady Hůrka. Dalším cílem bylo hodnocení možnosti prezentace 3D modelů v prostředí webu a nalezení optimálního řešení pro prezentaci na webu. V teoretické části jsou popsány možné metody pro hodnocení změn krajiny, vývoj krajiny v Česku od poloviny 19. století do současnosti, teorie 3D modelů, využití 3D modelů v praxi a možnosti prezentace 3D modelů. V praxi byly vytvořeny 2 modely krajiny vizualizované v ArcGIS Online Web Scene, CityEngine Web Viewer a 3D model zaniklé osady s průletovým videem a zobrazení současného stavu. Model byl vizualizován pomocí Sketchfab, 3DWarehouse a Google Poly. Vybráno bylo řešení pomocí Sketchfab, pro dobrou vizuální stránku a možnost zobrazení na mobilních zařízeních.The study deals with the model area of the village Prášily in Šumava (Bohemian Forest), which is analysed in the framework of the project "Heritage of lost landscapes: identification, reconstruction and presentation". The goal was to evaluate landscape changes since the middle of the 19th century until present with use of maps of stable cadaster, historical orthophotos, current ortophotos and to create 3D reconstruction models of the landscape and a 3D photorealistic model of the extinct village Hurka. The next aim was to evaluate possibilities of presentation of 3D models on the internet and to find an optimal solution for their web presentation. The theoretical part describes possible methods of evaluation of landscape transformation, development of landscape in the Czech Republic since the middle of 19th century, theory of 3D models, the use of 3D models in practice and the methods of presentation of 3D models. The practical part consists of two landscape models, that were visualized using ArcGIS Online Web Scene, Web Viewer and a 3D model of the extinct village Hůrka with fly- through animation. The models were created using Sketchfab, 3DWarehouse and Google Poly. Sketchfab was chosen as the best solution because of its good visuals and good display on mobile devices.Department of Applied Geoinformatics and CartographyKatedra aplikované geoinformatiky a kartografieFaculty of SciencePřírodovědecká fakult