# Application schemas

ISO 19109 defines an application schema as a "conceptual schema for data required by one or more applications." Its purpose is twofold: "to provide a computer-readable data description defining the data structure, which makes it possible to apply automated mechanisms for data management; and to achieve a common and correct understanding of the data, by documenting the data content of the particular application field, thereby making it possible to unambiguously retrieve information from the data."

ISO 19109 specifies "rules for creating application schemas in a consistent manner (including the consistent definition of features) to facilitate the acquiring, processing, analyzing, accessing, presenting and transferring of geographic data between different users, systems and locations. The rules are, in the case of data transfer or interchange, used by suppliers and users of geographic data to

- build a transfer application schema for data interchange;

- interpret the semantics of the transferred dataset with respect to user’s local data and content and structure of data; and

- determine the necessary transformations between the two datasets."

If such application schemas are modelled in UML using a specific UML profile, ShapeChange can be used to convert them to various target representations including transfer application schemas in XML Schema or JSON Schema.

ShapeChange accepts application schemas modelled using UML in one of the following formats:

- an Enterprise Architect project file

- an XMI 1.0 document

- a ShapeChange XML