m.transform(1grass) GRASS GIS User's Manual m.transform(1grass)
NAME
m.transform - Computes a coordinate transformation based on the con-
trol points.
KEYWORDS
miscellaneous, transformation, GCP
SYNOPSIS
m.transform
m.transform --help
m.transform [-srx] group=name order=integer [for-
mat=string[,string,...]] [input=name] [--help] [--verbose]
[--quiet] [--ui]
Flags:
-s
Display summary information
-r
Reverse transform of coords file or coeff. dump
Target east,north coordinates to local x,y
-x
Display transform matrix coefficients
--help
Print usage summary
--verbose
Verbose module output
--quiet
Quiet module output
--ui
Force launching GUI dialog
Parameters:
group=name [required]
Name of input imagery group
order=integer [required]
Rectification polynomial order
Options: 1-3
Default: 1
format=string[,string,...]
Output format
Options: idx, src, dst, fwd, rev, fxy, rxy, fd, rd
Default: fd,rd
idx: point index
src: source coordinates
dst: destination coordinates
fwd: forward coordinates (destination)
rev: reverse coordinates (source)
fxy: forward coordinates difference (destination)
rxy: reverse coordinates difference (source)
fd: forward error (destination)
rd: reverse error (source)
input=name
File containing coordinates to transform ("-" to read from stdin)
Local x,y coordinates to target east,north
DESCRIPTION
m.transform is an utility to compute transformation based upon GCPs and
output error measurements.
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.
NOTES
The transformations are:
order=1:
e = [E0 E1][1].[1]
[E2 0][e] [n]
n = [N0 N1][1].[1]
[N2 0][e] [n]
order=2:
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]
order=3:
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]
["." = dot-product, (AE).N = N’EA.]
In other words, order=1 and order=2 are equivalent to order=3 with the
higher coefficients equal to zero.
SEE ALSO
i.rectify, v.rectify, v.transform
AUTHORS
Brian J. Buckley
Glynn Clements
Hamish Bowman
SOURCE CODE
Available at: m.transform source code (history)
Accessed: unknown
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GRASS 7.8.7 m.transform(1grass)
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