Introduction to GML

GML (Geography Markup Language)

It is an XML-based spatial information encoding standard proposed by OpenGIS Consortium (OGC) and has received strong support from many companies, such as Oracle, galdos, Mapinfo, and cubewerx. Using GML, the encapsulated geographic data and graphic interpretation are clearly separated.

 

GML uses text to represent Geographical Information Based on XML

As GML can be seen as a specific word table of XML, it is easier to understand GML when you are familiar with XML. In addition, as XML is widely used, GML will also benefit. In addition, the text is simple, intuitive, and easy to understand and edit.

 

GML encapsulates geographical information and Its Attributes

Based on the Geographic Information Abstraction model, GML encapsulates spatial entity features and attributes. Geographical features include a series of attributes and corresponding geometric information. Generally, attributes consist of names, types, and values. geometric information consists of basic elements such as points, lines, surfaces, curves, and polygon. At present, GML is mainly confined to two-dimensional applications and is being expanded to two-dimensional semi-and three-dimensional spaces as well as the topological relationship between features. GML allows quite complex features, such as nesting between features. For example, an airport consists of taxi routes and aircraft runways.

 

GML encapsulates the spatial geographic reference system

Spatial geographic reference system is the basis for processing geographic information system data. GML encapsulates spatial geographic reference systems and main projection relationships to ensure the scalability and flexibility of distributed processing.

 

GML supports distributed storage of geographic data

GML is a very convenient technical means for geographic data distribution, but its role is not limited to this, it can also become an important means of geographic data distributed storage. The main technical tools are xlink and xpointer.