Optionally, the relationship of an observation to its image and image coordinates can be encoded with by-reference content items as Figure I.5-1 shows. For conciseness, the by-reference relationship points to the content item in the Image Library, rather than directly to the image.

R-INFERRED FROM relationships to IMAGE content items specify that the image supports the observation. A purpose of reference in an SCOORD content item may specify an analytic operation (performed on that image) that supports or produces the observation.