IndoorGML

IndoorGML
Name	IndoorGML
Extension	.gml, .xml
Mime	application/gml+xml
Developer	Open Geospatial Consortium
Latest release version	1.0.3
Latest release date	2020
Genre	Geographic data and information
Standard	OGC 14-005r6

IndoorGML. It is an open data model and XML-based encoding standard developed by the Open Geospatial Consortium for representing and exchanging spatial information about the interiors of buildings. The standard is designed to facilitate navigation, location-based services, and emergency response within complex indoor environments like airports, shopping malls, and office complexes. It complements other OGC standards such as CityGML and KML, focusing specifically on the topological and navigational relationships between indoor spaces rather than detailed architectural geometry.

Overview

The development of IndoorGML was driven by the growing need for sophisticated indoor spatial data frameworks to support applications in ubiquitous computing and the Internet of things. Its initial version was formally adopted by the Open Geospatial Consortium in 2014, following collaborative work by members from academia, industry, and government agencies. The standard provides a formal ontology for modeling indoor spaces as a network of navigable cells, which is crucial for pathfinding and spatial analysis. This approach distinguishes it from broader building modeling standards and enables interoperability with various navigation systems and sensor networks.

Core Concepts

The foundational concept in IndoorGML is the **Indoor Space**, which is decomposed into non-overlapping **Cells** representing navigable units like rooms, corridors, and elevators. These cells are interconnected via **Cell Boundaries**, such as doors and windows, forming a **Cell Space**. A key innovation is the explicit modeling of multiple, interconnected **Navigation Networks**—for example, separate networks for pedestrians, wheelchairs, or robotic platforms—within the same physical space. The standard also defines the **State**, representing a specific location within a cell, and the **Transition**, representing the movement between states, which is essential for representing precise movement and positioning system data.

Data Model and Representation

The data model is formally defined using Unified Modeling Language diagrams and implemented as an XML Schema Definition based on the Geography Markup Language framework. Geometries of cells are typically referenced externally from other datasets, such as Industry Foundation Classes or CityGML models, promoting data reuse. The core module defines the **CellSpace** and **CellBoundary** classes, while extension modules allow for specialized representations like **Multi-Layered Space** for multi-story buildings and **Anchor** for linking to external semantic web ontologies. This modular structure supports complex topological relationships critical for advanced spatial queries and 3D visualization engines.

Applications

Primary applications include indoor navigation and positioning systems for smartphones, often integrated with technologies like Bluetooth Low Energy beacons or Wi-Fi positioning system. It is heavily used for emergency response and evacuation planning by agencies such as the Federal Emergency Management Agency, enabling simulation of crowd movement. Other significant uses include facility management for large complexes like Changi Airport or the Dubai Mall, robotic navigation in warehouses, and spatial analysis for Internet of things sensor deployment. The standard also supports augmented reality applications that overlay digital information on physical indoor spaces.

Standards and Interoperability

IndoorGML is designed for interoperability with a suite of other Open Geospatial Consortium standards. It has a formal alignment with CityGML through the **Space Boundary** concept, allowing integration of detailed indoor models with broader urban contexts. The standard also references Sensor Observation Service for real-time data feeds and OpenLS for location services. Its development is coordinated with international bodies like the International Organization for Standardization, particularly within ISO/TC 211, to ensure alignment with foundational geographic information standards. This ecosystem enables seamless data exchange across planning, construction, and operational phases.

Implementations and Tools

Several commercial and open-source software libraries support IndoorGML. Notable tools include the **IndoorGML Viewer** from the University of Seoul and plugins for FME by Safe Software. Esri has incorporated support for the standard within its ArcGIS platform for indoor mapping solutions. Research institutions like the Fraunhofer Society have developed converters between Industry Foundation Classes and IndoorGML for the building information modeling domain. The open-source **geoserver** project also includes extensions for serving IndoorGML data, facilitating its use in web-based mapping applications and spatial database systems like PostGIS.

Category:Open Geospatial Consortium standards Category:Geographic data and information Category:XML-based standards