Grid ↔ Ground Converter — Combined Scale Factor
Point and line scale factor from MGA2020 grid coordinates, height factor from an ellipsoidal height or an AHD height plus an N value, and the combined scale factor — then convert a distance grid → ground or ground → grid with every step of the working shown.
Free advisory field tool — every result is computed in your browser from the inputs you provide and is advisory and unverified, not for survey deliverables. Where a published guideline applies, results only ever read “within guideline” or “exceeds guideline — review”. The full working is shown for every calculation so each step can be re-checked. Registered surveyor confirmation required before reliance.
Leave blank to compute the factors only.
Enter the point (and a height) to compute the factors — the result and its full working appear here.
Height note: the height factor needs the ellipsoidal height. If you work in AHD, supply the N value (geoid–ellipsoid separation) from your AUSGeoid model output and the tool shows the h = H + N step in the working — automatic AUSGeoid lookup is coming in a later update (B7.1). Line scale uses the precise Appendix C procedure with both endpoints held in the selected project zone.
Advisory output — confirm independently before reliance.
Safety & scope
SurveyMarkup helps prepare and review working information. Every professional decision remains with the registered surveyor, and original data and final outputs require qualified review.
Assistance only - professional review remains required.