Virtual reconstruction of historical landscape of Bely Gorod: Central area of Moscow, 17th – 18th centuries

1. The project tasks

Given the multidisciplinary nature of such a project, its team should include specialists from different fields: history, archaeology, geography, as well as architects, restorers, IT specialists (with experience in 3D, VR and GIS technologies). Such a team was assembled for the implementation of this project. Valid reconstruction of the historical city area should be carried out on the basis of a set of reliable historical sources (archaeological, geological, archival – pictorial, graphic, textual, etc.), characterizing the spatial changes in the territory of the Bely Gorod over two centuries.

The proposed virtual reconstruction of the historical landscape of the Bely Gorod for the first time makes it possible to assess the role of the anthropogenic factor, to reveal the influence of the expanding urban development on the evolution of the old city relief and urban environment. The digitized source base included hundreds of historical materials:

1. Citywide plans of Moscow and its central area of the 17^th – early 20^th centuries, including unpublished ones, which are kept in the collections of the Moscow and Federal archives (some of them with the designation of the elevation marks and contours of the relief).
2. Archival plans and drawings of individual estates of the 18^th – early 19^th centuries.
3. Text documents containing information about the owners and sizes of yards, construction works, etc.
4. Archaeological sources as well as data on geological wells and pits. Based on the sources representativeness, the second half of the 18^th century is taken as the main time slice in our reconstructions; however, in a number of cases, earlier time slices are also considered.

The following tasks were solved in our research:

• creation of a database on the city estates and buildings located on the territory of Bely Gorod;
• creation of a virtual reconstruction of the relief of the studied territory of the Bely Gorod;
• creation of 3D-models of the dominant historical buildings located on the Bely Gorod relief (Ivanovsky Monastery, temples, chambers, buildings of the city estates);
• placement (gridding) of objects’ 3D-models on the reconstructed relief;
• placement of the historical parceling of the Bely Gorod on the recreated relief;
• adjustment of the reconstructed landscape to use VR technologies to "immerse" the user in the virtual environment of the Bely Gorod.

The solution of the set tasks required the use of a number of digital technologies. Let us briefly consider how these technologies were used and what results of creating virtual reconstructions of the historical landscape and urban development of the Bely Gorod were obtained. In the framework of our project we made reconstructions for two periods – 17^th and 18^th centuries. In this paper we are concentrated on the reconstruction of the historical city area related to the middle of the 18 ^th century.

The recently published collective monograph (Stylianidis / Remondino 2016) devoted to the analysis of the experience of 3D representation, documentation and preservation of cultural heritage, includes a section on reconstruction of historical landscapes. The research tasks of our project demanded application of a wide range of digital technologies.

2. Methods and results

One of the methods for obtaining field data on partially preserved architectural heritage objects was 3D-scanning and aerial photography technology, using advanced technical means (laser scanner, copter). As examples of 3D-models made by different methods, this work presents the reconstruction of Prince Vladimir temple (17^th – 18^th centuries), the ensemble of the Ivanovsky Monastery (17^th – 18^th cc.) as well as the house (chamber) of A.F. Lopukhin, brother of Tsarina Evdokia Feodorovna, the first wife of Tsar Peter I. The identified sources allow us to offer verifiable reconstructions of their external appearance. However, in some cases, these models have a certain degree of convention, a reliable reconstruction of the space-planning composition of buildings can be combined with borrowing from analogs (Nocerino 2012).

In 2020, a 3D-scanning of the facades of the Vladimir temple (existing currently in a modified form) was carried out. Leica BLK 360 laser scanner was used. A large number of 3D-scanning points (73.7 million points) in the course of work made it possible to capture not only the exact appearance of the building, but also a large volume of the surrounding area of the temple. 3D-model of the temple appearance obtained from the point cloud was used to create a virtual reconstruction of the Vladimir temple based on retrospection techniques (Fig. 1). In hard-to-reach locations, where the capabilities of the laser scanner were limited (especially on the roof of the temple), it was necessary to conduct a combined survey of the temple also on a DJI Phantom 4 Standart unmanned aerial vehicle (UAV) (Fig. 2), with the subsequent construction of a point cloud based on aerial photography materials, combining two point clouds with each other and creating a 3D-model of the current state of the temple in the Agisoft Metashape program. The reconstruction of the 17^th century temple was carried out on the basis of its existing appearance, which made it possible to present the retrospective evolution of the temple from its present state to its original forms. The ArchiCAD program was used as the main tool for constructing a virtual reconstruction of the Bely Gorod buildings (see 3D-model of the temple at Fig. 3 and the Lopukhin chamber, Fig. 4).

Fig. 1. Reconstruction by point cloud (laser scanning) of the Temple of Prince Vladimir on the Pointbox site

Fig. 2. View of the dome of the temple of Prince Vladimir from a quadcopter

Fig. 3. Visualization of the virtual reconstruction of the temple of Prince Vladimir (evolution from 17^th to 18^th cc.)

Fig. 4. Visualization of the virtual reconstruction of Lopukhin chamber on the territory of the Bely Gorod (18^th century)

It should be noted that the relief of the Bely Gorod is rather complicated, the elevation difference here reaches several dozens meters, which required the creation of a three-dimensional map of this relief using the software capabilities of QGIS (Entin 2019). Fig. 5 shows a virtual reconstruction of the landscape of Bely Gorod, reflecting its parceling in the second half of the 18^th century. The features of the relief were carefully taken into account in the process of virtual reconstruction of the Ivanovsky monastery – the main dominant object (ensemble) on the territory of the Bely Gorod, located on the Ivanovskaya hill (this is one of the seven hills of Moscow), Fig. 6. The final stage of the project is associated with the use of virtual and augmented reality (VR / AR) technology.

Fig. 5. Virtual 3D-reconstruction of the landscape of the eastern part of Bely Good, reflecting its parceling in 18^th century (built in QGIS program)

Fig. 6. Visualization of the virtual reconstruction of the Ivanovsky monastery in the 18^th century)

All relevant sources, 3D-models, visual tours are represented at the project website (Landscape Project on MSU VR Center 2020).

As a result of this research, a three-dimensional reconstruction of the historical area of the 18^th century Moscow is obtained for the first time. This required the involvement of a large number of historical sources of different types and the complex application of a number of digital technologies.