OPTIMAS Metadata Concept Example. Data from different data domains are linked through metadata. The concept enables a user to get data from different data domains with specific characteristics of an experiment. In this example the metadata contains a sample of the nitrogen stress experiment. The measurement values are linked to these metadata. With this approach the user can for example extract the information, that in leaf 3 of sample 2(1) a fresh weight of 21.1 mg was measured.