The development of the real estate market necessitates a continuous need for analyses regarding the distribution of the number of transactions and level of transaction prices of real estate. This information is important for many market participants, such as investors, property owners, creditors, developers, as well as state and local government administration (for fiscal reasons). Transaction price data are systematically collected by administration units and are generally available to citizens. However, prices themselves do not provide sufficient information for the average user. Only when combined with geospatial data, they constitute complete and user-expected information. This publication analyses the distribution of unit transaction prices and the number of housing real estate transactions in the city of Katowice. A publicly available QGIS programme was used for the analysis. The results of the research proved the usefulness of the methodology used. Using the Voronoi diagram, the spatial distribution of the number of transactions in the studied area was presented. Using the methods of graphical data visualisation, the distribution of transaction prices in individual plats and the change in the distribution of transaction prices depending on the distance from the city centre were presented. In the case of the number of concluded transactions, plat 2 dominates, both on the primary and secondary market. In addition, in both cases, 2019 was the year with the most activity. Whereas, the highest transaction prices were recorded in 2020. In secondary trading, it was plat 14, and in primary trading – plat 3. The last year of the analysis is the period in which there was a large jump in prices, with a decrease in the number of transactions.