Distinguishing Component Parts of a <Model>
Decomposing a <Model> into component models allows the data provider to
- reuse component parts
- distinguish moving parts
Component vs. root model
- component model - only usable as a component of other <Models>
- root model - only usable within <Environment Roots>
- both - can be used in either context
One catch: Each <Model> has its very own spatial reference frame. How do we resolve this?