Abstract: A method for execution by a monitoring data analysis system includes receiving a plurality of measurement data from the gateway device, each indicating a measurement generated by one of a plurality of multi-sensor units. A set of measurement entries are generated based on the plurality of measurement data, and the set of measurement entries are added to a measurement database. A custom function definition for a custom function is received from a client device based on user input to a graphical user interface. Custom function output is generated by performing the custom function on a filtered subset of the plurality of measurement entries by utilizing the custom function definition. The custom function output is transmitted to the client device for display via the graphical user interface.