Enabling Geodetic Coordinate Reference Systems in Building Information Modeling for Infrastructure

The design and engineering of built facilities is performed in a Cartesian Coordinate System (CS). This CS is created by projecting the physical (curved) world onto a plane which introduces a distortion in lengths and... [ view full abstract ]

The design and engineering of built facilities is performed in a Cartesian Coordinate System (CS). This CS is created by projecting the physical (curved) world onto a plane which introduces a distortion in lengths and distances. When bringing the design information to the real world, a re-projection must be performed, i.e. the set- out values need to be calculated on the basis of the geodetic Coordinate Reference System (CRS) applied. This is a well-known process in geodesy, however it has also significant implications for Building Information Modelling (BIM) work flows, in particular when applied for long, linear civil engineering assets such as roads or railways.

In this paper, we take a close look at the vendor-neutral BIM data format Industry Foundation Classes (IFC) and investigate how it describes geodetic CRS. The support for georeferencing has been added in the latest version (IFC4) where the main reference is taken from the European Petroleum Survey Group (EPSG) database. However, it is very common that infrastructure projects define their own, project-specific geodetic CRS that cannot be referenced by an EPSG code. We propose an extension to the IFC data format to include support for such particularities by including grid shift datasets (e.g., NTv2).