The spatial coordination (coordinates) of the master BIM file is set at the beginning of the project. Once established, spatial coordinates should only be changed by mutual consent of the team and the Client’s Project Manager, with the matter recorded in the meeting minutes and the BMP. Once the design coordinate system is agreed upon, any model(s) of existing buildings relevant to the project are converted into the coordinate system used for each designed building.
A geo-reference to accurately locate the building within the site and to give it a physical location context at larger scales is included in the BIM file. The BIM Manager geo-references site plans and building models for site layout surveying and future Geographic Information System (GIS) use in accordance with AfriGIS. Latitude and longitude points for GIS purposes are also defined. The BIM file point and latitude/longitude points are located at an agreed point on site that is readily accessible during construction and will not be displaced. The MGA Reference will always “read” as 0,0,0 – the project base point will read whatever the distance is from the MGA Reference to the lowest left hand point of the building structural grid.