i.ortho.transform(1)

💖 i.ortho.transform 💖

okay bestie, welcome to the i.ortho.transform page from the GRASS GIS User's Manual — she's giving imagery girlie, she's giving orthorectify energy, and she is literally about to compute a coordinate transformation based on the control points. no cap. 🦋

✨ NAME ✨

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

🎀 KEYWORDS 🎀

imagery, orthorectify, transformation, GCP

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🌸 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

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👑 DESCRIPTION 👑

i.ortho.transform is a lil utility that computes transformation based upon GCPs and outputs error measurements. it's giving useful, fr fr. 💜

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. periodt.

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. (yes bestie, ignored. she said what she said. 💅)

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🔥 NOTES 🔥

Ortho-transformation is a 2-step transformation. First, source coordinates are transformed to sensor coordinates, then sensor coordinates are transformed to target coordinates. two steps, no shortcuts, that's the vibe check. ✨

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🌈 SEE ALSO 🌈

i.rectify

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💀 TODO 💀

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

(yes the manpage is literally roasting itself, we love an honest icon 😭)

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🫶 AUTHORS 🫶

• Brian J. Buckley
• Glynn Clements
• Hamish Bowman

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⭐ SOURCE CODE ⭐

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

Accessed: Saturday Jan 17 05:41:46 2026

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and that's the whole page, bestie!! 💖 this masterpiece was brought to you by the GRASS Development Team, © 2003-2025, living in the GRASS GIS 8.4.2 Reference Manual — that's the source and version, mwah. 💅✨ go transform something, you absolute main character. 🦋🌸👑