## 4 Discussion
Linking data from the SDI to the mobile Big Data set offers a possibility to evaluate and compare the legitimacy of maintaining or introducing a given new feature, as well as adjusting local zoning plan entries. The use of these data allowed us to \"balance\" the spatial development of the city and give it the right direction. In order to balance spatial development, it is necessary to understand the determination of such a destination for individual areas and choosing such parameters that will enable to avoid excessive intensification of both the development and the number of users. In addition, integrating Big Data sets with SDI allows us to create a new quality in deciding on places. The presented results fit into the concept of the platial nature of the city presented by [26] and confirming the conclusion drawn by [25] who stated that large amounts of user-generated content allow us to computationally analyze and quantify the shared meaning of place. As more planning practitioners are becoming aware of new opportunities that are brought by technology and different data sources and the ways to exploit them to deliver more transparent, participative, and well-informed policy and action [36; 37], the results presented in this paper reveal how information about users of mobile devices and some information from behavioral profiles may be analyzed for the purposes of verifying local zoning plans. The \"heat map\" and data from the PSDI allowed us to check what types of building generate an increased number of users to verify the assumptions concerning building facilities understood as structures, open areas, or objects, which accommodate or are intended to accommodate residential, civic, commercial, industrial, and/or mixed-use activities. Until now, it was a matter of some conjecture or knowledge based on not always precise data. Data from mobile devices (including smartphones and tablets) allowed us not only to specify the number of users, but also to properly define the concept of spatial development based on expert knowledge of urban planners. Proper orientation of spatial development should be understood primarily as compliance with the established spatial policy. Planned land use can be even better adapted to meet the needs of users of a given space. Obviously, the design process must be carried out in full form, that is, to examine all the conditions, including landscape, environmental, and cultural ones. In addition to the entire design process, new technologies allow urban planners to explore issues that were previously impossible to verify or to obtain the right data that was cost-effective. Linking detailed data on space users to buildings, cadastral parcels, and arable lands allowed for a more accurate definition of problem areas and possible solutions. The next step consisted in defining the principles of development and land use indicators. The use of Big Data allowed us to optimize the project, among other things, in terms of the movement of people. In this sense, urban planning should be treated [38] as a weave of related criteria constituting a complete system. Information about users of a given space may be obtained in many ways. In Poland these may be data collected by the given city, municipality or district office, as well as those that are available in the PSDI. Social networks and Big Data resources are also new sources of data that may be used as an additional source of knowledge. Together, these sources allow us to change the ways in which information about a place may be collected and analyzed. These collections and the analyses carried out on them may replace other sources of knowledge and research techniques. In order to obtain the data listed in Table 1, surveys should be organized and paid for. It is worth noting, however, that even the best surveys may initially be fraught with errors, and certainly would not apply to such a large number of people.