The problem of local databases autonomy in distributed information systems is widely known and has been solved for a long time by specialists, but there is still no unambiguous and universally recognized approach to solving this problem. The process of working with distributed databases when creating a geographic information system for decision support is not an exception, where the inviolability of the structure and completeness of local databases should remain the primary criterion for the system's operation. The purpose of the study is to increase the autonomy of local databases in geoinformation decision support systems based on the use of preprocessing processing of heterogeneous data. This article proposes approaches and specific solutions for the physical and logical representation of the geoinformation system structure by means of the implementation of the preprocessing mechanism, which will allow you to combine and transform data even before they are displayed in the application. Thus, a person making a decision, when working in a geoinformational decision support system, will have full access to up-to-date information with the ability to record the results obtained by saving a virtual database created at his request.