Table 1: permitted modifications of data

As given in EPSG dataset 
Permitted change for vendors / users to adopt 


4.1a 
Ellipsoid parameters a and b. 
a and 1/f ; a and f; a and e; a and e^{2}. 
4.1b 
Ellipsoid parameters a and 1/f. 
a and b; a and f; a and e; a and e^{2}. 


4.2a 
Lambert Conic Conformal (1 SP) method with projection parameters φ_{O} and k_{O}. 
Lambert Conic Conformal (2 SP) method with projection parameters φ_{1} and φ_{2}. 
4.2b 
Lambert Conic Conformal (2 SP) method with projection parametersφ_{1} and φ_{2}. 
Lambert Conic Conformal (1 SP) method with projection parameters φ_{O} and k_{O}. 
4.3a 
Mercator (variant A) method with projection parameters φ_{O} and k_{O}. 
Mercator (variant B) method with projection parameter φ_{1}. 
4.3b 
Mercator (variant B) method with projection parameter φ_{1}. 
Mercator (variant A) method with projection parameters φ_{O} and k_{O}. 
4.4a 
Hotine Oblique Mercator (variant A) method with projection parameters FE and FN. 
Hotine Oblique Mercator (variant B) method with projection parameters E_{C} and N_{C}. 
4.4b 
Hotine Oblique Mercator (variant B) method with projection parameters E_{C} and N_{C}. 
Hotine Oblique Mercator (variant A) method with projection parameters F_{E} and F_{N}. 
4.5a 
Polar Stereographic (Variant A) method with projection parameters φ_{O} and k_{O}. 
Polar Stereographic (Variant B) method with projection parameter φF. 
4.5b 
Polar Stereographic (Variant B) method with projection parameter φ_{F}. 
Polar Stereographic (Variant A) method with projection parameters φ_{O} and k_{O}. 
4.5c 
Polar Stereographic (Variant A) method with projection parameters φ_{O}, k_{O}, FE and FN. 
Polar Stereographic (Variant C) method with projection parameters φ_{F}, EF and NF. 
4.5d 
Polar Stereographic (Variant C) method with projection parameters φF, EF and NF. 
Polar Stereographic (Variant A) method with projection parameters φ_{O}, k_{O}, FE and FN. 
4.5e 
Polar Stereographic (Variant B) method with projection parameter FE and FN. 
Polar Stereographic (Variant C) method with projection parameters E_{F} and N_{F}. 
4.5f 
Polar Stereographic (Variant C) method with projection parameters E_{F} and N_{F}. 
Polar Stereographic (Variant B) method with projection parameter FE and FN. 


4.6a 
Position Vector 7parameter transformation method parameters R_{X} R_{Y} and R_{Z}. 
Coordinate Frame transformation method with signs of position vector parameters R_{X} R_{Y} and R_{Z} reversed. 
4.6b 
Coordinate Frame transformation method parameters R_{X} R_{Y} and R_{Z}. 
Position Vector 7parameter transformation method with signs of coordinate frame parameters R_{X} R_{Y} and R_{Z} reversed. 
4.7 
Concatenated transformation using geocentric methods (Geocentric translations, Position Vector 7parameter transformation, Coordinate Frame rotation). 
Equivalent single geocentric transformation in which for each parameter the parameter values of the component steps have been summed. 


4.8 
NTv2 method grid file filename. 
NTv2 method grid file relative storage path with file name including removal (if necessary) of “special characters” [spaces, parentheses, etc] which are replaced by underscore characters. 
4.9 
Parameter value. 
Convert unit to another, for example from microradian to arcsecond, using conversion factors obtained from the EPSG dataset Unit table. 