The study describes the stages of conceptual modeling to provide a crop monitoring system based on multi-source spatial data to assess the state of agricultural crops. The process of developing geodatabase models, which is the basis of the crop monitoring system, considered the construction of a set of diagrams of the Unified Modeling Language (UML). The UML Sequence diagrams have been developed to describe the specific properties of crop monitoring system components and their behavior. The developed Data flow diagram showed the data flow in the crop monitoring system and described the processes involved in the system for the transfer of data from source files to the geodatabase. The approach presented in the study can be suggested as a methodology that is suitable for a wide range of developers of monitoring systems.