Sustainability Ontology

A governed, machine-readable ontology for environmental and ESG data: 128 formally defined O-DEF terms across 3 axes, exposed through a semantic layer API for cross-system alignment and backed by a versioned registry with drift detection.

Three Semantic Axes

Every concept in the ontology is classified along three axes, so each term carries an unambiguous, machine-readable meaning.

Object Classes

What the data element represents (e.g., Resource, Process, Indicator, Ledger)

59
total
13 core
46 sustainability

Roles

The relationship or function of the data element (e.g., Emitter, Trader, Auditor)

27
total
10 core
17 sustainability

Properties

The measurable attribute (e.g., Measure, Amount, Factor, Rating, Identifier)

42
total
14 core
28 sustainability

Governed O-DEF Registry

The ontology is maintained as a versioned O-DEF registry. Changes are proposed, validated, and approved through a governed workflow so the definitions in git stay aligned with the models actually running in production.

Versioned approvals

Every release is a numbered version. Proposed changes become a draft, then a pull request that moves the approved pointer — the audit record lives in git.

Drift detection

The registry is continuously compared against the fields applied in the Open Footprint models. Renames and mismatches are flagged before they silently break consumers.

Validation gates

Registry submissions run the same server-side validation as CI. Breaking changes, numbering gaps, and source corrections are surfaced before approval.

Semantic Codes

Each ontology term carries a 3-axis semantic code. Codes are assigned using O-DEF™ (Open Data Element Framework), The Open Group standard we used to define the semantics.

ObjectClass~Role_Property

Example:

ofp-sustainability:3.1~1.1_5.1

Resource.Emission-Source ~ Trader.Emitter _ Measure.Greenhouse-Gas-Emission

Registry Coverage

59
Object Classes
27
Roles
42
Properties

Ontology Browser

Search and filter across 128 approved O-DEF registry terms.

Person

Object Classesobject class

A human being, whether man, woman, or child.

Semantic code1

Enterprise

Object Classesobject class

A collection of people organized to achieve a common set of goals.

Semantic code2

Enterprise.Reporting-Organization

Object Classesobject class

An enterprise that prepares and submits sustainability / GHG reports under a defined reporting boundary (organizational or operational).

Semantic code2.1

Enterprise.Supply-Chain-Partner

Object Classesobject class

An enterprise within the supply chain that contributes emission data for Scope 3 upstream or downstream categories.

Semantic code2.2

Enterprise.Organization-Association

Object Classesobject class

An association, membership, or relationship between organizations or between an organization and a person.

Semantic code2.3

Resource

Object Classesobject class

A source or supply from which benefit is produced. Typically, resources are materials, energy, services, knowledge, or other assets.

Semantic code3

Resource.Emission-Source

Object Classesobject class

A resource (fuel, feedstock, refrigerant, etc.) that directly or indirectly produces greenhouse gas emissions when consumed or processed.

Semantic code3.1

Resource.Emission-Sink

Object Classesobject class

A resource that removes greenhouse gases from the atmosphere (forests, soil, CCUS storage).

Semantic code3.2

Resource.Natural-Asset

Object Classesobject class

A natural resource subject to ESG reporting: water, minerals, biological assets.

Semantic code3.3

Resource.E-Ledger

Object Classesobject class

A ledger resource for tracking accountability balances, entries, debits, credits, and transfers.

Semantic code3.4

Resource.Equipment

Object Classesobject class

A physical asset - machinery, vehicle, meter, or installed unit - that consumes resources or produces emissions when operated.

Semantic code3.5

Location

Object Classesobject class

A place or position. Typically, locations provide geographic or geometric context that characterizes the data element.

Semantic code4

Location.Facility

Object Classesobject class

A physical installation, plant, or site where emission-producing activities occur.

Semantic code4.1

Location.Jurisdictional-Area

Object Classesobject class

A geographic area defined by regulatory or political boundaries relevant to compliance obligations.

Semantic code4.2

Location.Spatial-Reference

Object Classesobject class

A coordinate reference system, spatial transformation, or abstract spatial location used for geospatial data.

Semantic code4.3

Location.Address

Object Classesobject class

A postal or civic address identifying where an organization, person, or facility can be reached or is registered.

Semantic code4.4

Event

Object Classesobject class

An occurrence happening at some point or points in time, with or without the participation of human agents.

Semantic code5

Event.Emission

Object Classesobject class

A recording event capturing one or more emission measurements or calculations for a defined period.

Semantic code5.1

Event.Measurement-Environmental-Data

Object Classesobject class

A discrete sensor reading, sampling, or monitoring event producing raw environmental data (CEMS, meters).

Semantic code5.2

Event.Verification-Emission

Object Classesobject class

An audit, assurance, or verification activity applied to emission data.

Semantic code5.3

Event.Allocation-Emission-Quantities

Object Classesobject class

An event where emission quantities are allocated to facilities, activities, organizations, or products.

Semantic code5.4

Condition

Object Classesobject class

A particular mode of being of a person or thing; existing state; situation with respect to circumstances.

Semantic code6

Condition.Compliance-State

Object Classesobject class

The regulatory compliance status of an entity against a specific framework (CSRD, SEC, ISSB).

Semantic code6.1

Condition.Data-Quality-State

Object Classesobject class

The data quality condition of an emission record, assessed against PACT DQI dimensions.

Semantic code6.2

Condition.Quality-Rule-State

Object Classesobject class

A data quality rule, rule set, or assessment state used to evaluate and enforce data integrity.

Semantic code6.3

Condition.Non-Conformance

Object Classesobject class

A deviation from expected data quality, regulatory compliance, or internal standards requiring corrective action.

Semantic code6.4

Environment

Object Classesobject class

The natural or man-made surroundings of someone or something.

Semantic code7

Environment.Climate-Zone

Object Classesobject class

A climatic region that influences emission patterns and baseline assumptions.

Semantic code7.1

Environment.Ecosystem

Object Classesobject class

An ecological system relevant to biodiversity impact assessment.

Semantic code7.2

Law-Rule

Object Classesobject class

A law (natural or man-made) or policy that governs a process.

Semantic code8

Law-Rule.Regulation-Framework

Object Classesobject class

A regulatory or voluntary reporting framework governing sustainability disclosure (CSRD, SEC Climate, ISSB S2, EU ETS).

Semantic code8.1

Law-Rule.Emission-Standard

Object Classesobject class

A technical standard defining how emissions are measured, calculated, and reported (GHG Protocol, ISO 14064, ISO 14067).

Semantic code8.2

Law-Rule.Product-Category-Rule

Object Classesobject class

A product category rule (PCR) or environmental product declaration (EPD) standard governing product footprint calculation.

Semantic code8.3

Process

Object Classesobject class

A series of actions, changes, or functions bringing about a result.

Semantic code9

Process.Emission-Activity

Object Classesobject class

An activity that produces greenhouse gas emissions: combustion, fugitive release, industrial process, purchased energy.

Semantic code9.1

Process.Emission-Calculation

Object Classesobject class

The application of emission factors, allocation methods, or models to convert activity data into CO2e.

Semantic code9.2

Process.Emissions-Remediation

Object Classesobject class

An activity that reduces, offsets, or removes emissions: renewable energy, carbon capture, efficiency improvement.

Semantic code9.3

Process.Approval-Workflow

Object Classesobject class

A workflow process for reviewing and approving emission data, ledger entries, or reports.

Semantic code9.4

Process.E-Liabilities-Transfer

Object Classesobject class

A process for transferring e-liabilities between ledgers, organizations, or products along the value chain.

Semantic code9.5

Product

Object Classesobject class

The result of a process.

Semantic code10

Product.Carbon-Intensive-Production

Object Classesobject class

A product whose production generates significant embodied carbon (steel, cement, chemicals, aluminium).

Semantic code10.1

Product.Carbon-Footprint

Object Classesobject class

A product bearing a Product Carbon Footprint (PCF) as defined by ISO 14067 / PACT.

Semantic code10.2

Product.Lifecycle-Stage

Object Classesobject class

A stage within a product life cycle (raw material, manufacturing, distribution, use, end-of-life) relevant to PCF calculation.

Semantic code10.3

Substance

Object Classesobject class

A material of a particular kind that bears physical and chemical properties. Substances can be solid, liquid or gaseous.

Semantic code11

Substance.Greenhouse-Gas

Object Classesobject class

A gaseous substance contributing to radiative forcing: CO2, CH4, N2O, HFCs, PFCs, SF6, NF3.

Semantic code11.1

Substance.Pollutant

Object Classesobject class

A non-GHG substance causing environmental pollution: SOx, NOx, PM, VOCs.

Semantic code11.2

Substance.Water-Stewardship

Object Classesobject class

Water in any state relevant to water stewardship reporting: freshwater, wastewater, recycled water.

Semantic code11.3

Information-Set

Object Classesobject class

A collection of information, whether in physical form (such as a book), machine-readable form (such as a file on disc), or human memory.

Semantic code12

Information-Set.Emission-Report

Object Classesobject class

A structured report of emission data for a reporting period, conformant to a reporting framework.

Semantic code12.1

Information-Set.Audit-Trail-Record

Object Classesobject class

An immutable record documenting data lineage, transformation history, and custody chain.

Semantic code12.2

Information-Set.Conservation-Check

Object Classesobject class

A reconciliation record verifying mass-balance or ledger conservation (e.g., e-liability totals match).

Semantic code12.3

Information-Set.Reporting-Period

Object Classesobject class

A defined time interval for which emission data is collected and reported.

Semantic code12.4

Information-Set.Emission-Factor

Object Classesobject class

Reference information carrying emission conversion factors and their sources, used to derive emission quantities from activity data.

Semantic code12.5

Information-Set.Unit-Reference

Object Classesobject class

Reference information defining units of measure, unit systems, physical quantity kinds, and currencies used to express measured or monetary values.

Semantic code12.6

Information-Set.Emission-Inventory

Object Classesobject class

A structured inventory of emission sources and quantities for an organization or facility, organized by category for reporting.

Semantic code12.7

Service

Object Classesobject class

A valuable potential or actual action, deed, or effort to satisfy a need or to fulfill a demand.

Semantic code13

Service.Independent-Verification

Object Classesobject class

A third-party or internal service providing independent assurance of emission data.

Semantic code13.1

Service.OFP-Data-Ingestion

Object Classesobject class

A service that ingests, transforms, and maps raw data to the OFP Recording Domain.

Semantic code13.2

Service.Sustainability-Assurance

Object Classesobject class

A service providing formal assurance or attestation of sustainability reports and organizational boundaries.

Semantic code13.3

Trader

Rolesrole

Any role derived from any kind of trade relation of the implied or referenced object.

Semantic code1

Trader.Emitter

Rolesrole

An entity that produces greenhouse gas emissions and holds the resulting e-liability.

Semantic code1.1

Trader.Offsetter

Rolesrole

An entity that generates or purchases carbon offsets/credits to compensate for emissions.

Semantic code1.2

Trader.Supplier

Rolesrole

A supply chain partner providing embedded emission data for Scope 3 upstream categories.

Semantic code1.3

Lineage

Rolesrole

Any role derived from a relationship of the implied or referenced object with a common heritage.

Semantic code2

Lineage.Emission-Provenance-Chain

Rolesrole

The provenance chain tracing emission data from measurement point through processing to final report.

Semantic code2.1

Lineage.Product-Supply-Chain

Rolesrole

The supply chain lineage of embodied carbon through product life-cycle stages.

Semantic code2.2

Organized-Structure

Rolesrole

Any role derived from the configurational/organizational relation of an object.

Semantic code3

Organized-Structure.Reporting-Hierarchy

Rolesrole

An organizational hierarchy defining the reporting boundary (equity share, operational control, financial control).

Semantic code3.1

Organized-Structure.Address

Rolesrole

A postal or physical address structure within an organizational entity.

Semantic code3.2

Organized-Structure.Contact

Rolesrole

A contact person or point of contact within an organizational entity.

Semantic code3.3

Citizenship

Rolesrole

Any role derived from nationality of an implied or referenced person object.

Semantic code4

Proxy

Rolesrole

Any role derived from a kind of intermediation on behalf of an implied or referenced object.

Semantic code5

Proxy.Emission-Factor

Rolesrole

A proxy value used to convert activity data into estimated GHG emissions when direct measurement is unavailable.

Semantic code5.1

Proxy.Estimated-Value

Rolesrole

An estimated quantity derived from proxy data, models, or extrapolation rather than direct measurement.

Semantic code5.2

Proxy.Aggregation

Rolesrole

An aggregated or rolled-up value derived from detail-level records.

Semantic code5.3

Target

Rolesrole

Any role derived from a treatment with the intent to change an implied or referenced object.

Semantic code6

Target.Reduction-Goal

Rolesrole

A defined emissions reduction goal (SBTi-aligned, net-zero, absolute/intensity target).

Semantic code6.1

Target.Compliance-Threshold

Rolesrole

A regulatory threshold or cap that must not be exceeded (EU ETS allocation, EPA limits).

Semantic code6.2

Capability

Rolesrole

Any role derived from an acquired, trained, tuned, configurated or calibrated capability of an implied or referenced object.

Semantic code7

Capability.Emissions-Measure

Rolesrole

The ability to directly measure emissions via instruments (CEMS, flow meters, gas analysers).

Semantic code7.1

Collectiveness

Rolesrole

Any role derived from collective characteristics of implied or referenced objects.

Semantic code8

Collectiveness.Scope-Individual-Emissions-Aggregation

Rolesrole

The aggregation of individual emission records into Scope 1, 2, or 3 totals.

Semantic code8.1

Collectiveness.Portfolio-Multiple-Entities-Emissions-Aggregation

Rolesrole

The aggregation of emissions across multiple entities, facilities, or products into portfolio-level totals.

Semantic code8.2

Leveragability

Rolesrole

Any role derived from leveragability of an implied or referenced object.

Semantic code9

Leveragability.Intensity-Ratio

Rolesrole

A ratio expressing emission intensity relative to a business metric (revenue, production volume, FTE).

Semantic code9.1

Classifier

Rolesrole

The member acts as a controlled classification value - a type, category, status, or scheme entry - that categorizes instances of its object class rather than being an instance itself.

Semantic code10

Identifier

Propertiesproperty

A value that is intended to identify uniquely the object of the data element.

Semantic code1

Identifier.External

Propertiesproperty

An identifier originating from an external system, registry, or partner.

Semantic code1.1

Identifier.Reference

Propertiesproperty

A foreign key reference to another entity within the OFP data model.

Semantic code1.2

Name

Propertiesproperty

A word or phrase that refers to the object of the data element but is not intended to identify it uniquely.

Semantic code2

Code

Propertiesproperty

A value from an enumerated list of possible values that is not an Indicator and that is not subject to continual change.

Semantic code3

Code.Emissions-Scope

Propertiesproperty

A code categorizing emissions into Scope 1 (direct), Scope 2 (energy indirect), or Scope 3 (other indirect).

Semantic code3.1

Code.Emissions-Data-Quality

Propertiesproperty

A code representing data quality along PACT DQI dimensions (temporal, geographical, technological, reliability, coverage).

Semantic code3.2

Code.ESG-Governance

Propertiesproperty

A code representing ESG governance metrics (board diversity, policy compliance, anti-corruption).

Semantic code3.3

Code.Social-Performance

Propertiesproperty

A code representing social performance metrics (workforce safety, diversity, training, living wage).

Semantic code3.4

Code.Entity-Category

Propertiesproperty

A code classifying an entity into a type or category from a controlled vocabulary.

Semantic code3.5

Code.Lifecycle-Status

Propertiesproperty

A code representing the lifecycle or workflow status of an entity.

Semantic code3.6

Code.Verification-Status

Propertiesproperty

A code representing the verification or assurance status of a data element or report.

Semantic code3.7

Indicator

Propertiesproperty

A value that is one of only two (true or false) possible choices.

Semantic code4

Measure

Propertiesproperty

A numeric quantity that has an explicit or implied unit of measure other than a monetary unit.

Semantic code5

Measure.Greenhouse-Gas-Emission

Propertiesproperty

A measure of greenhouse gas emissions in a CO2-equivalent unit (kgCO2e, tCO2e).

Semantic code5.1

Measure.Water-Volume

Propertiesproperty

A measure of water volume (withdrawal, discharge, consumption) in cubic metres or equivalent.

Semantic code5.2

Measure.Biodiversity-Index

Propertiesproperty

A measure of biodiversity status or impact (MSA, BII, species richness index).

Semantic code5.3

Measure.Spatial

Propertiesproperty

A spatial coordinate, distance, or geometric measurement.

Semantic code5.4

Quantity

Propertiesproperty

An integral numeric quantity that has no unit of measurement.

Semantic code6

Quantity.Greenhouse-Gas-Emissions

Propertiesproperty

The total quantity of greenhouse gas emissions for a given activity, period, and scope.

Semantic code6.1

Quantity.Emissions-Activity-Drivers

Propertiesproperty

The quantity of an activity driver (kWh consumed, litres fuel burned, km travelled) used in emission calculations.

Semantic code6.2

Amount

Propertiesproperty

An explicit or implied monetary unit of measure.

Semantic code7

Amount.Carbon-Amount

Propertiesproperty

A monetary or physical amount specifically associated with carbon (carbon price, carbon tax, carbon credit value).

Semantic code7.1

Amount.Ledger

Propertiesproperty

A monetary or quantitative amount in a ledger context (balance, debit, credit).

Semantic code7.2

Rate

Propertiesproperty

A real numeric quantity, possibly expressed as a fraction, but not as a percentage.

Semantic code8

Rate.Greenhouse-Gas-Emission

Propertiesproperty

The rate of greenhouse gas emission per unit time (kg/hr, t/year) or per unit activity (kgCO2e/kWh).

Semantic code8.1

Percent

Propertiesproperty

A numeric quantity expressed as a percentage. Percent is a specialized Rate.

Semantic code9

Percent.Emissions-Reduction

Propertiesproperty

The percentage reduction of emissions relative to a baseline year or reference scenario.

Semantic code9.1

Date

Propertiesproperty

A specific date in the progression of time.

Semantic code10

Date.Period-Start

Propertiesproperty

The start date of a reporting, validity, or observation period.

Semantic code10.1

Date.Period-End

Propertiesproperty

The end date of a reporting, validity, or observation period.

Semantic code10.2

Date.Validity-Start

Propertiesproperty

The start date of a validity or applicability window for factors, rules, or registrations.

Semantic code10.3

Date.Validity-End

Propertiesproperty

The end date of a validity or applicability window for factors, rules, or registrations.

Semantic code10.4

Date-Time

Propertiesproperty

A specific date plus time in the progression of time.

Semantic code11

Date-Time.Effective

Propertiesproperty

The date-time when a record, rule, or status becomes effective.

Semantic code11.1

Date-Time.Termination

Propertiesproperty

The date-time when a record, rule, or status ceases to be effective.

Semantic code11.2

Time

Propertiesproperty

A specific time within a specific timeframe.

Semantic code12

Text

Propertiesproperty

Text that is not an identifier, name, code, indicator, measure, quantity, amount, rate, percent, date, date-time, or time.

Semantic code13

Text.Description

Propertiesproperty

Descriptive free text providing context about an entity or record.

Semantic code13.1

Text.Formula

Propertiesproperty

A textual formula, rule expression, or calculation specification.

Semantic code13.2

Text.Comment

Propertiesproperty

A free-text annotation, reviewer note, or explanatory comment.

Semantic code13.3

Binary

Propertiesproperty

A value that is not an identifier, name, code, indicator, measure, quantity, amount, rate, percent, date, date-time, time, or text.

Semantic code14

Semantic Layer API

The ontology is not just documentation — it is served as a semantic layer for cross-system alignment. Connectors and agents can look up the canonical meaning of a field, discover which fields share a semantic code, and map external data to Open Footprint without guesswork.

Cross-system alignment

A source-system field (e.g., SAP Material Group) can be related to its canonical counterpart (e.g., CPC Code) through a shared O-DEF semantic code, even when the names and formats differ.

GET /api/v1/ofp/semantics
GET /api/v1/ofp/semantics/{code}

Model-wide annotations

Every entity response carries field.odef data, and the semantic layer exposes which of the 660+ annotated fields share each code, complete with field-count cautions to avoid mapping onto noise.

Semantic Grounding Chain

O-DEF RegistryOFP AnnotationSemantic CodeSemantic APICross-System Map

The approved O-DEF registry annotates every Open Footprint data element with a 3-axis semantic code. That code is exposed through the semantic layer API so external systems — ERP, LCA tools, satellite pipelines — can map to the canonical model with confidence.

Alignment Ontologies

QUDT, SOSA, PROV-O, GeoSPARQL, and FIBO mappings from the O-DEF grounding chain.

Explore

Units of Measure

Energistics UoM as system of record, QUDT as its RDF face in the knowledge graph.

Explore

Semantic API

Natural-language and programmatic access to verified emissions data and model validation.

Explore