A Blockchain Solution for Securing Real Property Transactions: A Case Study for Serbia

The origins of digital money and blockchain technology goes back to the 1980s, but in the last decade, the blockchain technology gained large popularity in the financial sector with the appearance of cryptocurrencies such as Bitcoin. However, recently, many other fields of application have been recognized, particularly with the development of smart contracts. Among them is the possible application of blockchain technology in the domain of land administration, mostly as a tool for transparency in the developing countries and means to fight corruption. However, developed countries also find interest in launching pilot projects to test their applicability in land administration domain for reasons such as to increase the speed and reduce costs of the real property transactions through a more secure environment. In this paper, we analyse how transactions are handled in Serbian land administration and how this process may be supported by modern ledger technologies such as blockchain. In order to analyse how blockchain could be implemented to support transactions in land information systems (LIS), it is necessary to understand cadastral processes and transactions in LIS, as well as legislative and organizational aspects of LIS. Transactions in cadastre comprise many actors and utilize both alphanumeric (descriptive or legal) data and geospatial data about property boundaries on the cadastral map. Based on the determined requirements for the blockchain-based LIS, we propose a system architecture for its implementation. Such a system keeps track of transactions in LIS in an immutable and tamper-proof manner to increase the security of the system and consequently increase the speed of transactions, efficiency, and data integrity without a significant impact on the existing laws and regulations. The system is anticipated as a permissioned public blockchain implemented on top of the Ethereum network

Towards 3D Cadastre in Serbia: Development of Serbian Cadastral Domain Model

This paper proposes a Serbian cadastral domain model as the country profile for the real estate cadastre, based on the Land Administration Domain Model (LADM), defined within ISO 19152. National laws and other legal acts were analyzed and the incorrect applications of the law are outlined. The national “Strategy of measures and activities for increasing the quality of services in the field of geospatial data and registration of real property rights in the official state records”, which was adopted in 2017, cites the shortcomings of the existing cadastral information system. The proposed profile can solve several problems with the system, such as the lack of interoperability, mismatch of graphic and alphanumeric data, and lack of an integrated cadastral information system. Based on the existing data, the basic concepts of the Serbian cadastre were extracted and the applicability of LADM was tested on an obtained conceptual model. Upon obtaining positive results, a complete country profile was developed according to valid national laws and rulebooks. A table of mappings of LADM classes and country profile classes is presented in this paper, together with an analysis of the conformance level. The proposed Serbian country profile is completely conformant at the medium level and on several high-level classes. LADM also provides support for three-dimensional (3D) representations and 3D registration of rights, so the creation of a country profile for Serbia is a starting point toward a 3D cadastre. Given the existence of buildings with overlapping rights and restrictions in 3D, considering expanding the spatial profile with 3D geometries is necessary. Possible solutions to these situations were analyzed. Since the two-dimensional (2D) cadastre in Serbia is not fully formed, the proposed solution is to use the 2D model for simple right situations, and the 3D model for more complex situations

Extended LADM country profile for property valuation in Serbia

Real property valuation in the Republic of Serbia is a procedure in which the value of real property is defined on a certain date. Many different factors directly or indirectly affect the value of real property, and for that reason, the process of estimating the value of real property is very complex. In the Republic of Serbia, the field of real property valuation is regulated by appropriate laws and bylaws. Valuation of real property in the Republic of Serbia is done by different state bodies, and it is performed for different needs. A key element for real property valuation are public registers that enable regular maintenance and updating of data, as well as links between these registers that have the necessary information for assessment. The real estate cadastre provides data on real property that is necessary to assess the value of real property, however they are not sufficient for today’s complex valuation practice. By recording information produced through valuation activities and recording market indicators, it is possible to enable further market analysis, and more reliable real property valuation. The data sources for the real property valuation model are the real estate cadastre, the real estate price register and the central register of planning documents. In addition, other data sources can be used to provide an accurate and fair assessment of real property values. Real property valuation is performed by procedures of individual and mass real property valuation. Mass real property valuation is prescribed by the law and divided into four steps of which the first one is fully finished in Serbia. Republic Geodetic Authority implemented the Real Estate Price Register for that purpose. For the purpose of taxation, the value of real property is determined by usable area of the property and the average price per square meter of the corresponding real property in the zone where the real estate is located. The average price is determined based on the prices realized during the sale of appropriate real estate by zones. Taking into account the importance of real property valuation, an existing LADM country profile for Serbia (Radulović et al., 2017) is extended to include property valuation. The developed model for real property valuation is based on the LADM Valuation Information Model proposal (Kara et al., 2021) and appropriate national laws and bylaws. This model can be used for individual but also for mass valuation which is planned but not yet finished. Since data used for valuation come from different sources (Jočković, 2021), examples of specific valuation procedures are presented. One purpose of valuation is related to taxation process for which the tax administration is responsible. For this purpose, a web service architecture and mappings of appropriate data and code lists between geodetic authority and tax administration are discussed

Comparative analysis of length differences between georeference surfaces

The article deals with the length differences between georeference surfaces within the state coordinate system of Serbia. It’s an analysis starting from the topography, through geoid and ellipsoid, to the map projection. During the literature review, analyses of the length changes from topography to the state map projection for the geographic territory of Serbia were not found. The set of initial data consists DEM and the geoid model, as well as vector data that contain the boundary of the research area. Calculation will be performed on the basis of 88439 points of grids, located at a distance of 1 km, while the analysis will be done by comparing average deformations, extreme deformation values, percentage of positive and negative values of deformations, as well as percentage of length without deformations. The aim of this research is to provide a set of data on length differences that covers the entire territory of Serbia.The peer-reviewed version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3622

LADM Based Utility Network Cadastre in Serbia

The utility network cadastre in Serbia is the main register of utility lines and the rights to them. The Law on State Survey and Cadastre states the necessity for implementing a unified information system of both a real estate and utility network cadastre, but this has not been achieved in practice. The reasons for such a unified information system are to ensure easier maintenance of the rights of both the utilities and properties located above or below them, to ensure more efficient procedures for obtaining the consent for placement, repair, or removal of the utility line, to prevent procedures being executed based on outdated data, to build an information system as the law prescribes, and to facilitate the business processes in the Serbian geodetic authority, since it is responsible for both registers. Therefore, an already-developed LADM (Land Administration Domain Model)-based country profile for Serbia should be extended to include information from the utility network cadastre. An analysis of Serbian legislation showed the necessity of extending the class set of the utility network cadastre by further specialization of the LADM LA_LegalSpaceUtilityNetwork class. Furthermore, such a system will support the maintenance of utility network data. In practice, when there is a change made on utility lines by the right holders, it is necessary to implement the change in the register. In many situations, this is not done, and the actual state does not correspond to the one in the register. Usually, modern technologies, such as ground penetrating radar (GPR) and LIDAR, are used for data acquisition in order to provide an update of the utility network data. Since these technologies produce 3D data, we analyzed how to link that data to the traditional 2D spatial paradigm

Development of geoportal for landslide monitoring

The paper presents the implementation of geoportal for landslide monitoring which which includes two subsystems: a system for acquisition, storage and distribution of data on landslides and real time alert system. System for acquisition, storage and distribution of data on landslides include raster and vector spatial data on landslides affected areas, as well as metadata. Alert system in real time is associated with a sensor for detecting displacement, which performs constant measurements and signals in case of exceeding the reference value. The system was developed in accordance with the standards in the field of GIS: ISO 19100 series of standards and OpenGIS Consortium and is based on service-oriented architecture and principles of spatial data infrastructures. [Projekat Ministarstva nauke Republike Srbije, br. TR37017: Modeliranje stanja i strukture padinskih procesa primenom GNSS i tehnologija skeniranja laserom i georadarom

Comparative analysis of length differences between georeference surfaces

The article deals with the length differences between georeference surfaces within the state coordinate system of Serbia. It’s an analysis starting from the topography, through geoid and ellipsoid, to the map projection. During the literature review, analyses of the length changes from topography to the state map projection for the geographic territory of Serbia were not found. The set of initial data consists DEM and the geoid model, as well as vector data that contain the boundary of the research area. Calculation will be performed on the basis of 88439 points of grids, located at a distance of 1 km, while the analysis will be done by comparing average deformations, extreme deformation values, percentage of positive and negative values of deformations, as well as percentage of length without deformations. The aim of this research is to provide a set of data on length differences that covers the entire territory of Serbia

LADM based taxation model in Montenegro: Using BIM in taxation process

Real properties plays an integral role in the economy of every country. Considering this, property valuation and taxation processes are of great importance. Revenues from property taxes can be allocated to other areas thus improving the quality of life for all citizens. Since the valuation and taxation are related to properties themselves, the good cooperation between real estate cadastre and tax administration is necessary. Real estate cadastre submits current data on real properties and rights to them to the tax administration. These data and additional data on properties and their locations are then used to form a tax for citizens to pay. In the paper, an analysis of the legal regulations and laws, as well as the way of functioning of the current information system for the tax administration in Montenegro is performed in order to develop LADM based tax administration model. Developed model is an extension of previously developed LADM country profile for Montenegro. Based on the new model, an information system for tax administration is developed and all relevant procedures prescribed by the ‘Law on property tax’ (2019) and ‘Regulation on detailed criteria and methodology for determination of real property market values’ (2011), are implemented. The most important procedures are how to define the value of the property or how to calculate appropriate taxes. The basic criteria for determining the value of real properties are average market price per m2 of real property, purpose of the real property, size of real property, the place where the real property is located, quality of real property and other elements that may have an impact on the market value of real property. Every municipality defines the coefficients that correct the main formula for tax calculation. The new buildings have a BIM model created in a design phase which is a part of the documentation for issuing a building permit. Such BIM model can be used for at least two other purposes in addition to basic use. The first one is to serve as an input for 3D cadastre. Another reason is the use of BIM to calculate taxes. Data such as the area of the building and the quality of the building (building construction, building facade, windows, number of rooms, installations, number of bathrooms, etc.) can be directly loaded into database from the appropriate BIM model. Such solution can be resolved by expanding the regulative and the law to allow the use of this data. In the paper, the authors presented the mapping of entities from the BIM model to the appropriate code lists of the building quality and other attributes defined by the national regulation which are used to calculate tax. In this way, the tax calculation process would be accelerated and automated because the data from the project documentation would not be entered manually but would be taken over from BIM

Building Virtual 3D City Model for Smart Cities Applications: A Case Study on Campus Area of the University of Novi Sad

The Smart Cities data and applications need to replicate, as faithfully as possible, the state of the city and to simulate possible alternative futures. In order to do this, the modelling of the city should cover all aspects of the city that are relevant to the problems that require smart solutions. In this context, 2D and 3D spatial data play a key role, in particular 3D city models. One of the methods for collecting data that can be used for developing such 3D city models is Light Detection and Ranging (LiDAR), a technology that has provided opportunities to generate large-scale 3D city models at relatively low cost. The collected data is further processed to obtain fully developed photorealistic virtual 3D city models. The goal of this research is to develop virtual 3D city model based on airborne LiDAR surveying and to analyze its applicability toward Smart Cities applications. It this paper, we present workflow that goes from data collection by LiDAR, through extract, transform, load (ETL) transformations and data processing to developing 3D virtual city model and finally discuss its future potential usage scenarios in various fields of application such as modern ICT-based urban planning and 3D cadaster. The results are presented on the case study of campus area of the University of Novi Sad

Lessons learned from the Creation of the LADM based Country Profiles

A roadmap (consisting of six stages) to adopt the LADM in the cadastral information system has been provided in Kalantari et al (2015). Referring to this six-stage roadmap for LADM implementation, the paper focuses mainly on the stage 4 Data Organization, i.e. how different data entities are linked to each other. The LADM is regarded as a conceptual model that enforces certain relationships between the entities. On principle, there are three main ways in which the LADM based country profile can be developed: (1) to use LADM classes, attributes, code lists and relationships between classes “as is”, (2) to show an inherited structure between the LADM and the existing cadastral model, or (3) to show a mapping of elements between LADM and the existing cadastral model. The last two approaches will be probably used in countries with well-functioning cadastral information system. In this way the LADM based country profiles have also been created for Croatia (Vučić et al, 2015), Czech Republic (Janečka and Souček, 2017), Poland (Bydłosz, 2015), and Serbia (Radulović et al, 2017). Basically, the profiles for these four European countries have been proposed in academia. It means, that an initial activity for creation of the LADM based country profile didn’t come from the body or agency responsible for the cadastre (e.g. national mapping agency), but from academia. This activity could be seen as an irreplaceable role of the academia, to demonstrate the usefulness of the 3D cadastre and be a partner for government organizations. The paper explores the issues met during the preparation of the LADM based country profiles for these four countries when the “need” for LADM based country profile came from academia. The description of ways in which these issues were solved could help to those who are going to propose their new LADM based country profiles