Using a Geographic Coordinate System
A geographic coordinate system (GCS) can be applied to structural-scale and earth-scale data.
- Structure-scale data is used when designing buildings, stadiums, industrial plants, and other structures to assign the appropriate coordinate system for the structure. Design teams elect to place the origin at the front left corner of the building at ground level, with the positive X axis aligned with the front of the building, positive Y aligned with the side of the building and Z representing elevation above ground level. All data entry and readout is relative to that coordinate system. The geographic location and orientation of the structure are not considered in selecting the coordinate system.
- Earth-scale data is used when designing larger scale infrastructure, mapping, and surveying to select the appropriate projected geographic coordinate system that supplies a Cartesian coordinate system appropriate for the design location. When the same GCS is used for multiple design files, they can be easily referenced to each other. Referencing data that uses a different GCS, however, requires special calculations.
The Geographic Coordinate System dialog is used to view the geographic coordinate system (GCS) that is applied to your design data.