1m.transform(1) GRASS GIS User's Manual m.transform(1)
2
6 m.transform - Computes a coordinate transformation based on the con‐
7 trol points.
8
10 miscellaneous, transformation, GCP
11
13 m.transform
14 m.transform --help
15 m.transform [-srx] group=name order=integer [for‐
16 mat=string[,string,...]] [input=name] [--help] [--verbose]
17 [--quiet] [--ui]
18 Flags:
20 -s
21 Display summary information
22 -r
24 Reverse transform of coords file or coeff. dump
25 Target east,north coordinates to local x,y
26 -x
28 Display transform matrix coefficients
29 --help
31 Print usage summary
32 --verbose
34 Verbose module output
35 --quiet
37 Quiet module output
38 --ui
40 Force launching GUI dialog
41 Parameters:
43 group=name [required]
44 Name of input imagery group
45 order=integer [required]
47 Rectification polynomial order
48 Options: 1-3
49 Default: 1
50 format=string[,string,...]
52 Output format
53 Options: idx, src, dst, fwd, rev, fxy, rxy, fd, rd
54 Default: fd,rd
55 idx: point index
56 src: source coordinates
57 dst: destination coordinates
58 fwd: forward coordinates (destination)
59 rev: reverse coordinates (source)
60 fxy: forward coordinates difference (destination)
61 rxy: reverse coordinates difference (source)
62 fd: forward error (destination)
63 rd: reverse error (source)
64 input=name
66 File containing coordinates to transform ("-" to read from stdin)
67 Local x,y coordinates to target east,north
68
70 m.transform is an utility to compute transformation based upon GCPs and
71 output error measurements.
72 If coordinates are given with the input file option or fed from stdin,
74 both the input and the output format is "x y" with one coordinate pair
75 per line. Reverse transform is performed with the -r flag.
76 The format option determines how control points are printed out. A
78 summary on the control points can be printed with the -s flag. The
79 summary includes maximum deviation observed when transforming GCPs and
80 overall RMS. The format option is ignored when coordinates are given
81 with the input file option.
82
84 The transformations are:
85 order=1:
87 e = [E0 E1][1].[1]
88 [E2 0][e] [n]
89 n = [N0 N1][1].[1]
90 [N2 0][e] [n]
91 order=2:
92 e = [E0 E1 E3][1 ] [1 ]
93 [E2 E4 0][e ].[n ]
94 [E5 0 0][e²] [n²]
95 n = [N0 N1 N3][1 ] [1 ]
96 [N2 N4 0][e ].[n ]
97 [N5 0 0][e²] [n²]
98 order=3:
99 e = [E0 E1 E3 E6][1 ] [1 ]
100 [E2 E4 E7 0][e ].[n ]
101 [E5 E8 0 0][e²] [n²]
102 [E9 0 0 0][e³] [n³]
103 n = [N0 N1 N3 N6][1 ] [1 ]
104 [N2 N4 N7 0][e ].[n ]
105 [N5 N8 0 0][e²] [n²]
106 [N9 0 0 0][e³] [n³]
107 ["." = dot-product, (AE).N = N’EA.]
108 In other words, order=1 and order=2 are equivalent to order=3 with the
110 higher coefficients equal to zero.
111
113 i.rectify, v.rectify, v.transform
114
116 Brian J. Buckley
117 Glynn Clements
118 Hamish Bowman
119
121 Available at: m.transform source code (history)
122 Accessed: Saturday Oct 28 18:18:56 2023
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127 © 2003-2023 GRASS Development Team, GRASS GIS 8.3.1 Reference Manual
129GRASS 8.3.1 m.transform(1)