A data model is a way of defining and representing real world surfaces and characteristics in GIS. There are two primary types of spatial data models: Vector and Raster.
- Vector data represents features as discrete points, lines, and polygons
- Raster data represents features as a rectangular matrix of square cells (pixels)
GML is an XML grammar defined by the OGC to express geographical features, serving as a model for geographic systems as well as an open interchange format for geographic transactions.
A data model in geographic information systems is a mathematical construct for representing geographic objects or surfaces as data. For example, the vector data model represents geography as collections of points, lines, and polygons; the raster data model represent geography as cell matrices that store numeric values; and the TIN data model represents geography as sets of contiguous, nonoverlapping triangles.
In ArcGIS, a data model describes the thematic layers used in the applications (for example, hamburger stands, roads, and counties); their spatial representation (for example, point, line, or polygon); their attributes; their integrity rules and relationships (for example, counties must nest within states); their cartographic portrayal; and their metadata requirements.
CityGML is an open data model and XML-based format for the storage and exchange of virtual 3D city models. It is an application schema for the Geography Markup Language version 3.1.1 (GML3), the extendible international standard for spatial data exchange issued by the Open Geospatial Consortium (OGC) and the ISO TC211. The aim of the development of CityGML is to reach a common definition of the basic entities, attributes, and relations of a 3D city model. This is especially important with respect to the cost-effective sustainable maintenance of 3D city models, allowing the reuse of the same data in different application fields.
The OGC IndoorGML standard specifies an open data model and XML schema for indoor spatial information. IndoorGML is an application schema of OGC GML 3.2.1. While there are several 3D building modelling standards such as CityGML, KML, and IFC, which deal with interior space of buildings from geometric, cartographic, and semantic viewpoints, IndoorGML intentionally focuses on modelling indoor spaces for navigation purposes.
Keyhole Markup Language (KML) is an XML notation for expressing geographic annotation and visualization within two-dimensional maps and three-dimensional Earth browsers. KML was developed for use with Google Earth, which was originally named Keyhole Earth Viewer. It was created by Keyhole, Inc, which was acquired by Google in 2004. KML became an international standard of the Open Geospatial Consortium in 2008. Google Earth was the first program able to view and graphically edit KML files, but other projects such as Marble have added KML support.
The scope of the Land and Infrastructure Conceptual Model is land and civil engineering infrastructure facilities. Anticipated subject areas include facilities, projects, alignment, road, railway, survey, land features, land division, and “wet” infrastructure (storm drainage, wastewater, and water distribution systems). The initial release of this standard is targeted to support all of these except wet infrastructure.
PipelineML is a free data exchange standard designed to help oil and gas stakeholders move information quickly and easily. It was developed by an international group of pipeline operators, service providers, software vendors, and governmental agencies who invested countless hours of work on the standard from 2011 to 2019 (and the work is ongoing). It simplifies and expedites the process of sharing information across systems, software applications, and devices. This is accomplished by providing a universal data exchange format and a set of reference codes to enable everyone to speak a common language. Stakeholders do not need to change what they call things or which codes they use in their internal systems.
INSPIRE is "an EU initiative to establish an infrastructure for spatial information in Europe that is geared to help to make spatial or geographical information more accessible and interoperable for a wide range of purposes supporting sustainable development".
The INSPIRE directive lays down a general framework for a spatial data infrastructure (SDI) for the purposes of European Community environmental policies and policies or activities which may affect the environment. The INSPIRE Directive entered into force on 15 May 2007.
INSPIRE is based on the infrastructures for spatial information established and operated by the member states of the European Union. The directive addresses 34 spatial data themes needed for environmental applications.