Regarding geographic cloud computing, the three most crucial services are storage, processing, and visualisation. This cloud computing setup necessitates using the Internet of Spatial Things (IoST) technology. Users, planners, and environmentalists can all benefit from this technology because it can be used to build geospatially enabled smart environmental monitoring and assessment frameworks. There are many technical challenges in the IoST-enabled geospatial cloud environment, including scalability, security, privacy, and interoperability. Timely provision of real-time services is crucial for most environmental monitoring systems. The present work proposes a novel priority Queueing assisted IoST-Fog-Blockchain framework for the environmental monitoring and assessment system to resolve these issues. Temporarily storing geographical data, processing geospatial data, and visualising geospatial data are all services provided by the proposed framework, all of which can be accessed from the closest fog node. It minimises the Geospatial cloud servers' overload, traffic density, bandwidth requirements and service time. A novel priority Queueing analytical approach implies enhancing access control and ensuring the timely delivery of these services. Finally, it illustrates the several numerical outcomes that show how the proposed priority analytical model may be used to anticipate the performance indices of the presented system.