When a model used for geospatial purpose is drawn in cartesian coordinate system, it can be directly tied to a known geographic coordinate system. You can then use georeferencing to allow the models with varying projection systems to be attached and reprojected relative to the master model active coordinate system. Now consider a scenario where BIM projects located in a design model to optimize the design process (near the 0,0 of the file). In such a case a custom coordinate system may need to be created within that file. You can accomplish this by creating a series of placemark monument points that contain the latitude and longitude point coordinates, and subsequently create an azimuthal equal area project coordinate system, based on optimization of these points. The custom coordinate system can then be used to align other geospatially enabled data. Following general procedure explains the same.