14. A BMS system according to claim 6 comprising: data indicative of a plurality of facility model items which respectively describe physical locations within a building environment in terms of a category of location, and relationships with other locations, wherein a category of facility model items describe locations uniquely serviced by respective pieces of HVAC equipment; and data indicative of plurality of equipment model items, each equipment model item describing a specific piece of HVAC equipment in terms of a category of equipment selected from a set of available predefined categories of equipment, one or more data points associated with that piece of equipment, the roles of those data points, and relationships with one or more further pieces of equipment, wherein for at least one category of equipment the equipment model items include data indicative of a location uniquely serviced by that piece of equipment; such that the facility model items and equipment model items are linked by the locations uniquely serviced by respective pieces of HVAC equipment.
6. A building management system (BMS) comprising: a physical memory for storing a repository of non-transitory data that is indicative of plurality of equipment model items, these equipment model items based on predetermined equipment model templates, such that each equipment model item describes a specific piece of equipment in terms of a category of equipment selected from a set of available predefined categories of equipment, one or more data points associated with a piece of equipment belonging to that category, the roles of those data points, and relationships with one or more further pieces of equipment; a user interface that accepts input from a user to define each equipment model item to describe a specific physical installed piece of mechanical equipment in terms of data as required by one of the predetermined equipment model templates, wherein for a given physical installed piece of mechanical equipment, the user interface is configured to accept input to: (i) select, from the repository of equipment model templates, a category of equipment which describes the physical installed piece of mechanical equipment; and (ii) for each of the one or more data points associated with the selected category of equipment, associate the data point with a physical installed control level item associated with the physical installed piece of mechanical equipment, being a control level item from which data is received by the BMS, such that the BMS is configured to attribute data receive from that control level item with that data point; and a visualization module including a physical display for automated visualization of the equipment model items defined to represent physical installed pieces of mechanical equipment in terms of location and relationships.