## 1 Introduction  
This study is a continuation of the research presented in the article [1]. The comparative approach is recognised as one of the most widely used and considered to be one of the most reliable methods of property valuation [2]. It involves comparing the property to be valued with others that have recently been sold on the local property market. The basis of this approach is data on comparable transactions in which the usable area of the property plays a key role [3, 4]. In Poland, valuers use the Real Estate Price Register (REPR). It is a database that is accessible to authorised professionals and is located in the local County Office. It contains information on property prices, derived from notarial deeds. The REPR was introduced in 2001 and updated in 2021 to comply with new legislation [5]. The data in this database relate to all purchase/sale transactions, and covers the entire country. The REPR is a practical source of real estate data that is linked to other state registers [6, 7, 8, 9, 10, 11]. Although the REPR is an important tool to support property valuation, its main drawback is the incompleteness of the data, especially with regard to the usable floor area of residential buildings. Research carried out in the West Pomeranian Voivodeship, in the districts of Koszalin and Kolobrzeg, showed that only in 40% of cases was information on the usable area of the properties under investigation available in the REPR [12; 13; 14]. Such deficiencies significantly hamper the comparison of properties and may lead to errors in valuations, especially in small local markets where the number of comparable transactions is severely limited. Given the limitations of the REPR in terms of data completeness, one potential solution to the lack of floor area data is the use of the publicly available Database of Topographic Objects (BDOT10k). BDOT10k is a detailed spatial database developed for the entire territory of Poland. It contains topographic information, including data on buildings, transportation networks, watercourses, land use, and other landscape features [15; 16; 17]. For buildings, the database includes parameters such as height, length, width, and perimeter. The data sources include geodetic measurements and airborne laser scanning (LiDAR) technology. In this study, data on buildings located in Koszalin were obtained from the Geoportal in CityGML 2.0 format [18] and processed using QGIS Desktop v. 3.28.2 software [19]. Missing information, such as the number of floors, was supplemented using observations from Google Street View [20]. In Poland, LiDAR datasets are available in LoD1 and LoD2 formats. The LoD1 configuration features a density of 4 points/m\({}^{2}\) but does not include detailed roof geometry. The second level, LoD2, has a higher density of 12 points per m\({}^{2}\) and includes a detailed roof structure, including building height and additional building elements such as garages. Most LiDAR data in Poland are available at the LoD2 level, but for the residential buildings in Koszalin analysed in the article, only the LoD1 level is available, which limits the ability to estimate their height. Limitations in scanning accuracy at the LoD1 level can lead to significant errors in the assessment of building heights, which can be as high as 50%. This was calculated using Monte Carlo simulations in an earlier article [21]. In Poland, the quality of LiDAR scanning varies regionally. In the western part of the country, including Koszalin, the LoD1 standard applies, while in the eastern part, the more detailed LoD2 standard is used. In this paper, in order to avoid height measurement errors at the LoD1 level at this stage of the proposed method, building heights measured by surveyors were used. In this article, we analyse detached residential buildings with multi-pitched roofs. These roofs are characterised by having more than two pitched planes that intersect at various angles [22]. They are primarily valued for their functionality, aesthetic appeal, and durability.