Galdos Systems develops XML and GML application schemas and GML profiles for companies and organizations around the world, as well as XSLT scripts for transforming data from one schema to another.
As one of the original creators of the Geography Markup Language (GML), Galdos has significant expertise in working with GML schemas. GML application schemas provide an essential ingredient in geospatial data sharing by specifying a common language for filters, queries, and responses. Sharing a common language through GML or XML schemas is a critical component in data sharing and interoperability.
Establishing Common Vocabularies
GML schemas are a way to establish the community vocabulary in a shared application domain. Schemas and frameworks such as the Common Alerting Protocol (CAP) and the National Information Exchange Model (NIEM) are used to define specific data structures for messages in domains such as emergency management. There are a number of publicly accessible GML schemas, including:
- AIXM – the Aeronautical Information eXchange Model
- CityGML – a common information model and GML application schema for virtual 3D city and regional models
- DAFIF – an information model for defense aviation
GML Application Schemas and Profiles
Sometimes, a complete GML schema is not necessary to describe the data for a domain, and a GML schema may be made up of a number of sub-schemas, each of which describes a specific part of the dataset. At other times, Galdos has developed or used appropriate GML Profiles when that is all that is needed for a specific project.
A GML Profile is an expression of a subset of a GML schema that is used within a specific application domain. These profiles are intended to simplify adoption of GML, and to facilitate rapid adoption of the standard. A number of GML profiles have been published or proposed for public use including the GML Simple Features profile (supporting vector feature requests and transactions in, for example, a Web Feature Service), and the GML profile for GMJP2 (GML in JPEG 2000).
GML Profiles are distinct from application schemas in that profiles are part of GML namespaces and define restricted subsets of GML, while application schemas are XML vocabularies defined using GML and they live in a namespace that is defined by the application space.
Working with GML Schemas
Galdos offers a number of products and tools for working with and viewing GML data such as INscape (a Web Feature Service), INspector (an application for viewing and working with GML and CityGML), INview (a viewer for GML data in JPEG2000 images), and GML SDK (a tool for working with GML data).
Galdos is an active participant in the Open Geospatial Consortium (OGC), which maintains GML, and is the co-chair of the OGC GML standards working group.
