I am writing to request a critical update to SurPad’s coordinate system management. Currently, SurPad is unusable for professional construction surveying because its mathematical logic is the exact opposite of industry standards like Stonex Cube-a. The Fundamental Flaw: SurPad vs. Stonex Logic SurPad Logic (Grid-Centric): Your software treats the Map (Grid/Ellipsoid) as the absolute truth. It forces physical ground measurements to "shrink" or "stretch" to fit a cartographic projection. This is a "backwards" approach for site surveyors. Stonex Logic (Ground-Centric): Stonex treats the Ground as the absolute truth. It captures the Combined Scale Factor from the very first point received by the GNSS and locks it. It then adapts the coordinate system to the physical reality of the site, ensuring a consistent 1:1 scale. The Evidence (Real Field Tests): In my tests, SurPad constantly recalculates the scale factor as I move, leading to unacceptable discrepancies: Point A: Combined Factor 0.999978. Point B: Combined Factor 1.000008. Because the software works "backwards," I am forced to "trick" it by entering false elevations (e.g., -3000m) just to try and reach a 1.000000 scale. This is prone to error and unprofessional. Requested Feature - "Ground Mode": I request a feature that allows SurPad to operate like Stonex: Capture & Lock: The software must derive the Scale Factor from the first measured point (Origin) and lock it for the entire project. 1:1 Ratio: It must ensure that 100 meters measured by GNSS equals 100 meters on the ground (Total Station compatibility). Geoid Adaptation: It must adapt these measurements to the Geoid (Square/Quadratic) for correct elevations without distorting the horizontal 1:1 scale. We need SurPad to prioritize the Ground over the Grid. This is the only way to ensure that GNSS and Total Stations can work together on the same site. I look forward to a technical response regarding the implementation of this "Ground-Centric" logic.

Attached you will find a screenshot from Stonex Cube-a. This is exactly what I am requesting for SurPad. As you can see, Stonex allows the user to set a 'Ground' system where the scale factor is derived from the first point and then kept constant. Notice how the software handles the relationship between the Ellipsoid and the Ground: it adapts the math to the site, not the site to the map. In SurPad, I am missing this 'Site-Calibration-First' logic. Please compare how Stonex manages the Combined Scale Factor versus SurPad’s current dynamic (and backwards) calculation.