1m.transform(1)              GRASS GIS User's Manual             m.transform(1)
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NAME

6       m.transform   -  Computes a coordinate transformation based on the con‐
7       trol points.
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KEYWORDS

10       miscellaneous, transformation, GCP
11

SYNOPSIS

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
19   Flags:
20       -s
21           Display summary information
22
23       -r
24           Reverse transform of coords file or coeff. dump
25           Target east,north coordinates to local x,y
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27       -x
28           Display transform matrix coefficients
29
30       --help
31           Print usage summary
32
33       --verbose
34           Verbose module output
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36       --quiet
37           Quiet module output
38
39       --ui
40           Force launching GUI dialog
41
42   Parameters:
43       group=name [required]
44           Name of input imagery group
45
46       order=integer [required]
47           Rectification polynomial order
48           Options: 1-3
49           Default: 1
50
51       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
65       input=name
66           File containing coordinates to transform ("-" to read from stdin)
67           Local x,y coordinates to target east,north
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DESCRIPTION

70       m.transform is an utility to compute transformation based upon GCPs and
71       output error measurements.
72
73       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
77       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

NOTES

84       The transformations are:
85
86       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
109       In  other words, order=1 and order=2 are equivalent to order=3 with the
110       higher coefficients equal to zero.
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SEE ALSO

113        i.rectify, v.rectify, v.transform
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AUTHORS

116       Brian J. Buckley
117       Glynn Clements
118       Hamish Bowman
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SOURCE CODE

121       Available at: m.transform source code (history)
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123       Main index | Miscellaneous index | Topics  index  |  Keywords  index  |
124       Graphical index | Full index
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126       © 2003-2020 GRASS Development Team, GRASS GIS 7.8.5 Reference Manual
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130GRASS 7.8.5                                                     m.transform(1)