m.transform
Computes a coordinate transformation based on the control points.
m.transform [-srx] group=name order=integer [format=string [,string,...]] [input=name] [--verbose] [--quiet] [--qq] [--ui]
Example:
m.transform group=name order=1
grass.script.run_command("m.transform", group, order=1, format="fd,rd", input=None, flags=None, verbose=False, quiet=False, superquiet=False)
Example:
gs.run_command("m.transform", group="name", order=1)
Parameters
group=name [required]
Name of input imagery group
order=integer [required]
Rectification polynomial order
Allowed values: 1-3
Default: 1
format=string [,string,...]
Output format
Allowed values: 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
-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
--qq
Very quiet module output
--ui
Force launching GUI dialog
group : str, required
Name of input imagery group
Used as: input, group, name
order : int, required
Rectification polynomial order
Allowed values: 1-3
Default: 1
format : str | list[str], optional
Output format
Allowed values: idx, src, dst, fwd, rev, fxy, rxy, 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)
Default: fd,rd
input : str, optional
File containing coordinates to transform ("-" to read from stdin)
Local x,y coordinates to target east,north
Used as: input, file, name
flags : str, optional
Allowed values: s, r, x
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
verbose: bool, optional
Verbose module output
Default: False
quiet: bool, optional
Quiet module output
Default: False
superquiet: bool, optional
Very quiet module output
Default: False
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.ortho.transform, i.rectify, v.rectify, v.transform
AUTHORS
Brian J. Buckley
Glynn Clements
Hamish Bowman
SOURCE CODE
Available at: m.transform source code
(history)
Latest change: Friday Feb 07 19:16:09 2025 in commit a82a39f