Surveyors deal with small but important adjustments to their field surveys day after day. One adjustment that is often ignored, but it shouldn’t be, is what we often refer to as “Scale Factor”. An understanding of how the scale factor is applied to field observations and office calculations is important when dealing with grid coordinates i.e. Map Grid of Australia (MGA94).
Whether a surveyor uses GPS, Total Station or both (Leica SmartStation), scale factor cannot be ignored. The challenge for surveyors is to use GPS without misunderstanding what the scale factors are. This will only become more complicated when introducing a Total Station that produces ground distances, integrated with GPS, that produces coordinates that are related to a predefined datum.
This figure shows the combined scale factor for the Map Grid of Australia [Lands Department, NSW]