As Vecorel is targeting multiple encodings, there's no single solution for validation. We must define our own validation vocabulary, based on the Vecorel SDL data types. Nevertheless, Vecorel SDL can be translated into JSON Schema.

• Schema identifier: https://vecorel.org/sdl/v0.2.0/schema.json
• Metaschema (as JSON Schema)

The following keywords are generally supported:

• type: The Vecorel data types as a string, required.
• deprecated: Indicates whether a schema is deprecated.
• default: Indicates the default value of a schema.
• description: Describes the schema.

At the top-level, you can also indicate the following special properties:

• $schema: The schema identifier, see above.
• required: The required properties (see required for objects below).
• properties: The schemas for the properties (see properties for objects below).
• collection: Specifies whether a property (specified as keys) must be provided only at the collection-level (true) or only at the feature-level (false). Omit any properties that can be provided at both levels.

Additionally, the following validation vocabulary per data type is defined by JSON Schema.

In principle any keywords available in JSON Schema 2020-12 can be used, but it is likely unsupported by the Vecorel tooling.

• format (values: email, idn-email, iri, uri, uuid)
• pattern
• minLength
• maxLength
• enum

• minimum
• maximum
• exclusiveMinimum
• exclusiveMaximum
• enum (for integer data types only)

• items (required, object only, sub-schema must be compliant to Vecorel SDL)
• minItems
• maxItems
• uniqueItems
• contains (sub-schema must be compliant to Vecorel SDL)

• required
• properties (sub-schemas must be compliant to Vecorel SDL)
• additionalProperties (Note: In objects additional properties are disallowed by default, i.e. the default value is false. In JSON Schema the default value is true. Sub-schemas must be compliant to Vecorel SDL)
• patternProperties (sub-schemas must be compliant to Vecorel SDL)
• minProperties
• maxProperties (>= 1)

Either properties, additionalProperties or patternProperties must be provided.

• geometryTypes (not part of JSON Schema): A list of allowed geometry types. Any of: Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon