If coordinates are given with the input file option or fed from
stdin
, both the input and the output format is "x y" with one
coordinate pair per line. Reverse transform is performed with the
-r flag.
The format option determines how control points are printed out. A summary on the control points can be printed with the -s flag. The summary includes maximum deviation observed when transforming GCPs and overall RMS. The format option is ignored when coordinates are given with the input file option.
order=1:
e = [E0 E1][1]·[1] [E2 0][e] [n] n = [N0 N1][1]·[1] [N2 0][e] [n]
e = [E0 E1 E3][1 ] [1 ] [E2 E4 0][e ]·[n ] [E5 0 0][e²] [n²] n = [N0 N1 N3][1 ] [1 ] [N2 N4 0][e ]·[n ] [N5 0 0][e²] [n²]
e = [E0 E1 E3 E6][1 ] [1 ] [E2 E4 E7 0][e ]·[n ] [E5 E8 0 0][e²] [n²] [E9 0 0 0][e³] [n³] n = [N0 N1 N3 N6][1 ] [1 ] [N2 N4 N7 0][e ]·[n ] [N5 N8 0 0][e²] [n²] [N9 0 0 0][e³] [n³]
In other words, order=1 and order=2 are equivalent to order=3 with the higher coefficients equal to zero.