Proposal to extend the I-ADOPT Framework to support the aggregation of I-ADOPT variables


One important use case of the I-ADOPT Framework is the necessity to link I-ADOPT variables to multiple broader concepts. This is not only to facilitate their discovery by a range of end-users across a broad variety of applications, domain specialism and/or language registry, but also to support aggregation of variables in data products. 

Many examples for this requirement can be found in various research domains. Below are some  emerging ones from the environmental domains:

  • Essential Ocean Variables (EOV), are groups of variables used for the quantification of key ocean processes, selected for their relevance, feasibility and cost-effectiveness. Grouped by topics, they are described in the Global Ocean Observing System (GOOS)’s specification sheets

  • Essential Climate Variables (ECV), are groups of variables used to characterise the Earth’s climate also grouped by topics and layer

  • Essential Biodiversity Variables (EBV), are groups of variables classified into species and ecosystem-focused themes

  • eLTER Standard Observations (SO), classifications of variables into different categories of the Ecosystem Integrity concept


Extension proposal to the I-ADOPT Framework:

This proposal is open for comments until March 31 2023. For anybody wanting to discuss the approach or propose variations to this extension please use the commenting functions via this I-ADOPT github page


In order to categorize I-ADOPT variables under one or multiple grouping concepts, it is necessary to extend the I-ADOPT framework adding a new class for the grouping concepts and four new relations, as follows:



An aggregation class to group a set of variable for a specific purpose

Example: EOV “Nutrients”, ECV “ Precursors for Aerosols and Ozone”, EBV “Ecosystem function”, example



Domain: VariableSet                       Range: Property                        Cardinality 0..n

A VariableSet has one or more applicable Properties

Example: The EOV “inorganic carbon” may regroup variables with the following applicable I-ADOPT properties: “alkalinity”, “pH”, “concentration” (of dissolved inorganic carbon), “partial pressure” (of carbon dioxide)



Domain: VariableSet                  Range: ObjectOfInterest               Cardinality 0..n

A VariableSet has one or more applicable ObjectOfInterest.

Example: The EOV “nutrients” may regroup variables with the following chemical substances as applicable “object of interest”: nitrate, nitrite, ammonium, phosphate, silicic acid (or silicate). 



Domain: VariableSet                 Range: Matrix                                 Cardinality 0..n

A VariableSet has zero or many applicable Matrices.

Example: The EBV “Ecosystem function” may regroup variables with measurement of primary productivity in different environmental domains or matrices (e.g. in sea water, in sediments, in ice)



Domain: VariableSet              Range: ContextObject                      Cardinality 0..n

A VariableSet has zero or many applicable ContextObjects.

Example: The SO “Soil inventory” may regroup variables with measurements in the geosphere as context object


ro:hasMember (

Domain: VariableSet            Range: Variable                                 Cardinality 0..n

A VariableSet has one or many Variables as members.

Example: The SO “Soil inventory” may regroup variables like amount of organic matter, soil bulk density, soil pH value.

Figure1: Extended I-ADOPT Framework by VariableSet and associated relations

After the presentation of the extension at the 20th Plenary in Gothenborg we have agreed to change the cardinalities of the proporties hasApplicableProperty and hasApplicableObjectOfInterest to 0..n as this might be considered useful in some cases but must not be a constraint.

See these use cases that apply the extension of the I-ADOPT Framework.


Image icon I-ADOPT-extension.jpg28.42 KB