What is Geo-Referencing?
Geo-referencing aligns your BIM files so that they can be federated accurately, ensuring precision and design coordination.
According to the
CORENET X Code of Practice,
- The development and all its elements should be geo-referenced to coordinates from the Singapore SVY21 coordinate system (EPSG: 3414) for Easting and Northing (x, y) and Singapore Height Datum (SHD) for Height (z).
- A correctly geo-referenced location will contain the project’s base point and survey points in SVY21 coordinates including dimensions between grids.
- The layout of the site model shall be presented in True North or real-world orientation. Elevation levels of the model shall be set up based on the Singapore Height Datum (SHD) of 0.000m.
Why is There a Need to Geo-Reference BIM Models?
Standardising the geo-referencing of BIM models to the SVY21 coordinate system and the Singapore Height Datum (SHD) offers several key advantages.
| Enhanced Interoperability |
Allows BIM data from different workflows and software to be easily consolidated in the correct location(s) |
| Improved Contextualisation |
Situates development accurately with reference to the surrounding virtual 3D context for urban analysis |
| More Precise Regulatory Checks |
Enables further geospatial analysis and more accurate regulatory checks (e.g. building height check) |
| Efficient Archival and Retrieval of BIM Data for Future Reference |
Allows BIM models to be archived in the correct geo-referenced location and easily retrieved for future reference for regulatory checks or comparisons with future submissions |
How Do I Geo-Reference My BIM Model?
Learn more about how to input coordinates to your model in your native BIM software:
Geo-Referencing Revit Files
Revit does not have an in-built global coordinate system, so specifying coordinates and having a geo-referenced linked file with shared coordinates may be needed to set more accurate survey point(s) that provide a real-world context to the Revit model.
| Method 1: Specify coordinates |
If you know the SVY21 coordinates that a certain point in the model is supposed to correspond in the real-world:
Use ‘Specify Coordinates at Point’ tool: Select a reference point in the model and specify the correct [X]-Easting, [Y]-Northing, [Z]-Elevation coordinates and Angle to True North for it. The model’s coordinates and Project Base Point will then be adjusted accordingly to reflect their proximity to the reference point. See here for guide. |
| Method 2: Linking a CAD / DWG file and acquiring the coordinates |
If you have a CAD/ DWG file of the site which has already been geo-referenced to the real world:
Via ‘Acquire coordinates’ tool: Link a site DWG file and acquire its coordinates for geo-referencing. Refer to this guide and tutorial video for more information. |
Geo-Referencing ArchiCAD Files
See full
step-by-step guide for ArchiCAD 20 to 24. Refer to Section on ‘Storeys, Project Location and Reference Levels’.
Method: Setting up Project Location and True North
|
Go to ‘Options’, choose ‘Project References’ and ‘Project Location’: Input the Easting, Northing and Elevation values for the model’s [X], [Y] and [Z] coordinates, and specify the angle for Project North.
Note:
- The Easting, Northing and Elevation values are to be entered by changing the sign in mm. If it is positive, change it to negative (or vice versa).
- For Altitude, you may enter in SHD form (eg, For SHD 104, enter 4 into Altitude).
|
Geo-Referencing OpenBuildings (formerly AECOsim) Files
See
step-by-step tutorial.
Method: Setting Geographic Coordinate System
|
- Go to ‘Coordinate System’ and select SVY21 under Singapore’s library
- Link all reference files (.dgn) relevant to the project
- Specify the real-world site coordinates for all the reference files in the ‘References’ pop-up window, in the offset X, Y, Z boxes.
|
Other Resources
The Singapore Institute of Surveyors and Valuers - Land Surveying Division has also come up with a video on geo-referencing, to explore how land surveyors and architects can work together to have more efficient workflow for future CORENET X submission.
For feedback or enquiry related to CORENET X, please complete this form.