In many cases, XML or GML is not the ideal way to structure (geo)data. Although excellently structured, databases are often getting very big due to the tag system, which can lead to performance problems, especially when you want to exchange large amounts of data via mobile internet.
An alternative to XML is JSON. JSON is very easy to learn and has now established itself in many applications, as it allows data to be structured in a simple way and the data can be exchanged between servers and web applications.
JavaScript is THE language of the Internet and JSON itself is a valid JavaScript, that’s why JSON can be executed directly in the browser or converted into a JavaScript object. This achieves a close integration of data and application.
Very important: JSON is based on objects (hence object notation), whereby an object consists of an unordered set of attribute-value pairs. An object begins with ‘{’ and ends with ‘}’. Each attribute is followed by a colon followed by the value.
“Study”: “UNIGIS”
means, for example, that the attribute ‘Study’ has the value ‘UNIGIS’. The attribute-value pairs within an object are separated from each other by commas.
Listings (so-called ‘arrays’) are enclosed in square brackets [], whereby the list elements are separated from each other by commas, just like the attribute-value pairs.
A value can be a number, a character string (string), a list (array), a logical expression (true, false) or another object. This means that the structures can be nested within each other.
GeoJSON (Geographic JavaScript Object Notation) was developed as a JSON variant for the efficient exchange of simply structured geodata. Although it is not yet an official standard, GeoJSON has become a de facto standard for exchanging geodata over the Internet thanks to its efficient data structure and the correspondingly small files. GeoJSON offers web developers an easy way to extend existing APIs and has been adopted by many services such as Twitter and GitHub.
