The correct formula to solve the coefficient p for geographic to grid conversion is:

• A. p = 0.000001(E)
• B. p = 0.00001(E')
• C. p = 0.0001(E')
• D. p = 0.000001(E')

Answer: (C)

In geographic to grid conversion, the small correction term p grows with the Easting and is expressed as a tiny fraction of the corrected Easting. Using the corrected Easting, E', ensures the adjustment aligns with the grid’s final coordinates after all local corrections have been applied. The standard scale factor here is 1/10000, so p = 0.0001 × E'. This keeps the correction small and consistent across the grid.

Using E would base the correction on an unadjusted value, and using a larger or smaller multiplier would misrepresent the intended level of distortion correction (0.00001 or 0.000001 would be an order of magnitude off). Therefore, the appropriate form is p = 0.0001(E').