Problem statement

In the context of railway infrastructure description and usage, we need to reconcile two representations:

• large-scale representation of sites, typically using local cartesian coordinates, a domain in which BIM excels;
• small-scale representation of railway lines, typically using geographic coordinates such as GPS coordinates or projected coordinates.

Standards

ISO/TR 23262:2021 GIS/BIM interoperability

GEOBIMM approach

According to the GEOBIMM project Slo01(#Slo01), the aim is to ensure:

• the appropriate geometric description of the elements;
• the correct georeferencing;
• the geospatial semantic and topological interoperability between the two systems;
• the appropriate definition of the information parameters.

According to the same source, the challenge (as of 2022) is a practical one, namely the lack of interoperable file formats and suitable tools. To address these issues, GEOBIMM delivered guidelines which we will take inspiration from in the limited context of the FP1 project. Obviously, all proposals derived from these guidelines will have to be reviewed and discussed by bodies dedicated to BIM in order to test them for validity and acceptance. Results obtained before the closure of the Project will be reported here.

GIS: capabilities and limitations of GeoSPARQL

Versions and announcements

GeoSPARQL is currently available under version 1.1. Version 2.0 is announced with a list of foreseen features, but no due date Ogc02(#Ogc02).

(Geo)SPARQL endpoint capabilities

Limited 3D

GeoSPARQL can handle 3D data storage by means of extended serialization formats: WKT-Z instead of WKT, or GML version 3. Also, in absence of serialized data, 3D geometries can be earmarked using the property geo:is3D.

Note 1: WKT and WKT-Z are OGC standards; about WKT-Z, see OGC 06-103r4 Ogc03(#Ogc03). In addition, the WKT format for CRS (Coordinate Reference Systems) is standardized as ISO 19162.

Note 2: GML3 (i.e. version 3) is an OGC standard, also published as ISO 19136:2007.

However, to date, GeoSPARQL spatial functions, such as geof:sfIntersects, only consider 2D projections. Vertically stacked bodies would be identified as intersecting.

Possible workarounds include hybrid software solutions, using PostGIS functions such as ST_3DIntersects, or custom GeoSPARQL extensions such as those provided aby Apache JENA.

True 3D capabilities are intended to be added to GeoSPARQL 2.0 Ogc01(#Ogc01).

GIS information in IFC

Present situation (IFC 4.3 ADD2)

IFC 5 perspectives

The relationship between IFC and GIS is one of the identified subjects on the IFC evolutionary path.

References

[Cle01]: Bridging the gap between geospatial and construction, Christian Clemen, Ana Roxin, published by GIM International, feb. 14, 2020

[Ogc01]: https://github.com/opengeospatial/ogc-geosparql/issues/28

[Ogc02]: https://github.com/opengeospatial/ogc-geosparql/milestone/3

[Ogc03]: https://www.ogc.org/standards/sfa/ (ISO 19125)

[Slo01]: The IFC file format as a means of integrating BIM and GIS: the case of the management and maintenance of underground networks, Cinzia Slongo & al., in ISPRS Annals of Photogrammetry, Vol. V-4-2022, June 2022, Nice, France