i.ortho.transform(1)

NAME
i.ortho.transform - Computes a coordinate transformation based on the control points.

KEYWORDS
imagery, orthorectify, transformation, GCP

SYNOPSIS
i.ortho.transform
i.ortho.transform --help
i.ortho.transform [-srxp] group=name [format=string[,string,...]] [coords=name] [--help] [--verbose] [--quiet] [--ui]

  Flags:

-s
    Display summary information

-r
    Reverse transform of coords file or coeff. dump
    Target east,north,height coordinates to local x,y,z

-x
    Display transform matrix coefficients

-p
    Enable panorama camera correction

--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

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)

coords=name
    File containing coordinates to transform ("-" to read from stdin)
    Local x,y,z coordinates to target east,north,height

DESCRIPTION
i.ortho.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 z" 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
Ortho-transformation is a 2-step transformation. First, source coordinates are transformed to sensor coordinates, then sensor coordinates are transformed to target coordinates.

SEE ALSO
i.rectify

TODO
Update this document with x,y,z<->E,N,H information

AUTHORS
Brian J. Buckley
Glynn Clements
Hamish Bowman

SOURCE CODE

Available at: i.ortho.transform source code (history)

Accessed: Sunday Jun 21 14:59:37 2026

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