Copyright © 2015 Open Geospatial Consortium.
3 Please check the Bibliography at the end of this document for additional references.
3 Terms and definitions
For the purposes of this report, the definitions specified in Clause 4 of the OWS Common Implementation Standard [OGC 06-121r9] shall apply. In addition, the following terms
and definitions apply.
3.1
array one of the data types that the value of a JSON key can have. I contains a sorted list of
unnamed values
NOTE In fact, in JavaScript, an array is an object that has keys with consecutive numerical names.
3.2
declaration associate an JavaScript object with a name of a data type.
3.3
define Describe an JavaScript object data type by providing a list of its key properties, data type
declarations and multiplicities.
NOTE As you will read later in the text JSON-LD is able to declare but not to define.
3.4
key a JSON text that will represents the name of a variable in the JavaScript Document
Object Model.
3.5
object one of the data types that the value of a JSON key can have. It contains a list of property
keys.
4 Conventions
4.1 Abbreviated terms
Some more frequently used abbreviated terms: AJAX
Asynchronous JavaScript And XML API
Application Program Interface
4
Copyright © 2015 Open Geospatial Consortium.
DOM Document Object Model
JSON JavaScript Object Notation
JSON-LD JavaScript Object Notation for Linked Data
OWL Web Ontology Language
RDF Resource Description Framework
WKT Well Known Text
XML Extendable Markup Language
4.2 UML notation
Diagrams that appear in this standard are presented using the Unified Modeling Language UML static structure diagram, as described in Subclause 5.2 of [OGC 06-121r3].
5 JSON overview
This ER Topic addresses JSON and GeoJSON in OGC standards. JavaScript Object Notation JSON is an open standard format that uses human-readable
text but also a machine readable encoding to transmit data objects consisting of attribute– value or arrays of values pairs. The attribute is a quoted text and the values can be a
quoted text, a number, or the words true, false and null. JSON is used primarily to transmit data between a server and web application, as an alternative for XML.
Although originally derived as a subset of JavaScript scripting language, JSON is a language-independent data format. Code for parsing and generating JSON data is
available in many programming languages such as C++ or Java.
JSON is currently described by RFC 7159 and ECMA-404. The ECMA standard is minimal, describing only the allowed grammar syntax, whereas the RFC also provides
some semantic and security considerations. The official Internet media type for JSON is applicationjson. The common JSON filename extension is “.json” but specific
applications of JSON usually recommends other file extensions that contains the word “json” such us “.geojson”.
This is an example of a river described in JSON:
{ river:
{ name: mississipi,
length: 3734, discharge: 16790,
source: Lake Itasca, mouth: Gulf of Mexico,
