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Core Specification

This specification describes the core data and metadata properties that describe a Vecorel Feature. The specification doesn't distinguish between collection-level and feature-level properties, common definitions are shared across these levels.

Table of Contents

General Properties

Property Name Data Type Description
schemas object<string, array<string>> REQUIRED. A list of schemas the collection implements.
id string REQUIRED. An identifier for the entity.
collection string REQUIRED. The identifier of the collection.

schemas

The schemas the collection implements. Each schema must be a valid HTTP(S) URLs to an existing YAML files compliant to Vecorel SDL. The schema for this specification (see above) is required to be provided.

Each collection must have a single set of applicable schemas. The key of the dictionary must be equal to the value provided for the collection property.

The schema URI for Vecorel that is listed above is required to be present.

Example for schemas:

This describes two collections abc and xyz.

{
  "abc": [
    "https://vecorel.org/specification/v0.1.0/schema.yaml"
  ],
  "xyz": [
    "https://vecorel.org/specification/v0.1.0/schema.yaml",
    "https://vecorel.org/crop-extension/v0.1.0/schema.yaml",
  ]
}

id

It must be unique per collection, i.e. collection and id form a unique identifier.

collection

A collection is a group of one or more features with a unique identifier, stored in the collection property.

Encodings may support to store properties that consists of the same value across all features at the collection-level. This de-duplicates data for more efficient resource usage, but only applies if more than two features are available for the collection. The specific location and behaviour of collection-level data is specified in the encoding-specific specifications.

Example:

You have two different datasets named abc (CC-0 licensed) and xyz (CC-BY-4.0 licensed). If you store the datasets separately, you can store the license in the collection-level data as the value for the property is the same for all features. Once you merged the two datasets, you must ensure that a unique identifier for the collection is provieded (here: abc and xyz) so that IDs are unique. Additionally, you have to add the license property on the feature-level as the licenses are now twofold.

Spatial Properties

Property Name Data Type Description
geometry geometry REQUIRED. A geometry that reflects the footprint of the described entity. Default CRS is WGS84.
bbox bounding-box The bounding box of the geometry.

Schema Language

The schema language used for Vecorel is Vecorel SDL, version 0.2.0.

The data types in the tables above are defined in the document Data Types.

Vecorel SDL defines a (limited) set of data types and a vocabulary to express additional constraints for these data types. This allows to define a clear mapping between the core specification and its encodings.