VISUALISING AUSTRALASIA'S SOILS

Visualising Australasia’s Soils Background Technical Build CeRDI Observations System VAS System API

VAS Systems API

The VAS Systems API forms the backbone of the CeRDI Observation System, enabling transparent and interoperable access to soil and environmental data across Australasia.
It translates complex research datasets into structured, linked data accessible through machine-readable endpoints.

Developed in alignment with W3C and OGC best practices, the API follows a RESTful PostgREST architecture. All payloads are served in JSON-LD, ensuring seamless integration with semantic-web applications and supporting FAIR data principles (Findable, Accessible, Interoperable, Reusable).

Core Design Principles

  1. Standards Compliant Ontologies: built on SOSA/SSN, Schema.org, QUDT, PROV, SKOS, GeoSPARQL and ANZSoilML.

  2. Persistent Identifiers: each entity dataset, feature, observation, property, procedure has a stable URI under https://id.cerdi.edu.au/

  3. Machine Interoperability: JSON-LD contexts link to controlled vocabularies and ontology URIs.

  4. Open API Specification: a public OpenAPI definition is available on SwaggerHub.

Base Endpoint

Base URI     :  https://id.cerdi.edu.au
Framework    :  PostgREST
Response     :  JSON-LD
Auth Header  :  Authorization: Bearer <API_KEY>

Public datasets can be queried without authentication, while private datasets require valid API keys provided to partner organisations.

Primary Resources and Endpoints

Resource

Endpoint Pattern

Example URI

Description

Feature

/{provider}/data/sosa/feature
/ccma/data/sosa/feature/ccma.soil.feature.7174

Returns soil features (e.g., sites, layers, samples) with spatial geometry and metadata.

Observation

/{provider}/data/sosa/observation
/ccma/data/sosa/observation/ccma.soil.observation.10840

Returns measured soil property values linked to feature, dataset and procedure.

Dataset

/{provider}/data/schema/dataset
/ccma/data/schema/dataset/000001

Lists dataset metadata such as project origin, provider and licence.

Observed Properties

/query/observedproperties/{provider}
/query/observedproperties/ccma

Lists soil or environmental attributes measured (e.g., pH, EC, Bulk Density).

Procedures

/query/procedures/{provider}
/query/procedures/ccma?limit=20

Returns the methods used for observations, including units and descriptions.

Property-Procedure Links

/query/propertyprocedures/{provider}
/query/propertyprocedures/ccma

Maps each observed property to its valid measurement procedure.

Query Capabilities (ODATA Syntax)

The API supports advanced ODATA-style queries for:

  • Filtering: ?or=(observedProperty->>"@id".eq.<URI>, provider.eq.ccma)

  • Attribute Selection: ?select=provider,f_geom,hasResult

  • Pagination and Ordering: ?limit=20&order=observation_time.desc

Example query for bulk density observations:

https://id.cerdi.edu.au/ccma/data/sosa/observationsearch/
?observedProperty->>
"@id".eq.http://placeholder.cerdi.edu.au/property/bulk_density_soil
&limit=20
&select=provider,f_geom,hasResult

Sample Observation Response

{
"@type": "Observation",
  "provider": "ccma",
  "observedProperty": "pH",
  "numericValue": 5.2,
  "unit": "pH",
  "featureOfInterest": "ccma.soil.feature.7174",
  "usedProcedure": "pH of 1:5 soil/0.01 M CaCl₂ extract – 4B4",
  "dataset": "ccma.schema.dataset.000001",
  "phenomenonTime": "2018-05-15T00:00:00Z"
}

Integration and Usage

The VAS Systems API acts as the integration bridge between:

  • the CeRDI Observations System backend (PostgreSQL database views),

  • external federated soil repositories (e.g., CCMA, Agriculture Victoria, SFS),

  • and the VAS Portal front-end, which visualises datasets through interactive maps and graphs.

Each endpoint returns semantically rich JSON-LD data for direct consumption by web clients, dashboards, and data analytics applications such as Tableau and QGIS.

Authentication and Licensing

Access is tiered:

  • Public Data: Accessible under Creative Commons licences.

  • Partner Data: Requires API Key authentication in the HTTP header: Authorization: Bearer <API_KEY>

Supported Ontologies & Vocabularies

The VAS Systems API is the final publication layer in the data lifecycle, transforming raw field measurements into discoverable linked data. It supports data federation between regional contributors and enables cross-institutional insights for environmental monitoring, agriculture, and policy development across Australia and New Zealand.

To know more information regarding API: API Documentation