Definition
GeoJSON is a geospatial data interchange format based on JavaScript Object Notation (JSON). It defines several types of JSON objects and the manner in which they are combined to represent data about geographic features, their properties, and their spatial extents. Because it's light-weight and easily readable, GeoJSON is widely used in many geographic and GIS applications that are web-based, and is supported by a wide range of software.
What is GeoJSON?
GeoJSON is a format designed for representing simple geographical features, along with their non-spatial attributes. It’s based on the JSON standard and used by a wide array of applications to represent 3D geometry, spatial features, and spatial relationships. Its key strength is the straightforward and compact structure of JSON, not requiring any preliminary setup or parsing. It supports point, line, polygon, MultiPoint, MultiLineString, MultiPolygon and GeometryCollection where the latter can represent a combination of the above types.
In a GeoJSON file, data is organized in a structure called a "feature collection," which is a set of "features." A "feature" represents a spatial object and its associated properties. Each feature has two properties: a geometry (which can be a point, line, polygon, etc.) and a set of 'properties' (which are descriptive attributes associated with the feature).
FAQs
How is GeoJSON used in GIS?
In GIS, GeoJSON is often used for transferring data between servers and web map applications, as it can easily be read and created by JavaScript. GeoJSON files are often small enough to be downloaded and processed in a web browser.
What is the difference between JSON and GeoJSON?
JSON is a lightweight data-interchange format that is easy to read and write by humans and easy to parse and generate for machines. GeoJSON is a specialized format based on JSON designed specifically for the representation of geographical features. GeoJSON extends JSON by providing definitions for geographical features such as Points, Lines, and Polygons.
Why is GeoJSON preferred over XML for geospatial data?
GeoJSON is preferred over XML in many cases because it's simpler, less verbose and easier to use. GeoJSON is native to JavaScript and thus works seamlessly in web development. XML requires extra parsing and hence has more overhead.
What is the structure of a typical GeoJSON object?
A typical GeoJSON object consists of a 'type', 'geometry', and 'properties'. The 'type' can be Feature, Point, LineString, etc. The 'geometry' describes the spatial attributes and data. The 'properties' are feature attributes which can contain any information the spatial feature holds.
Can GeoJSON represent complex geographic features?
Yes, GeoJSON can represent complex geographic features. Although simple geographic entities such as points, lines, and polygons can be directly represented, complex structures like MultiPoint, MultiLineString, MultiPolygon, and GeometryCollection allow more complex representation of geographic features.
