i.ortho.camera(1)

📦
version 8.4.2 · 8 versions
, in fedora 44

💖 i.ortho.camera 💖

okay bestie, welcome to the GRASS GIS User's Manual, and this is the page for i.ortho.camera(1) — the vibe is imagery, orthorectify, and honestly? it's giving "your camera needs its little reference file and we're here to make it happen." 🌸

✨ NAME ✨

i.ortho.camera — bestie this one selects and modifies the imagery group camera reference file. that's the whole job. slay. 💅

🔑 KEYWORDS 🔑

imagery, orthorectify

✨ SYNOPSIS ✨

i.ortho.camera
i.ortho.camera --help
i.ortho.camera  [group=name]  camera=name  [name=string]   [id=string]
[clf=float]   [pp=east,north]   [fid=east,north[,east,north,...]]
[--help]  [--verbose]  [--quiet]  [--ui]

🚩 Flags 🚩

  • --help — prints the usage summary. your little cheat sheet, no cap 📝
  • --verbose — verbose module output. it's gonna yap (affectionately) 🗣️
  • --quiet — quiet module output. shhh, it's doing its thing 🤫
  • --ui — forces the GUI dialog to launch. pop off, graphical era 🪟✨

🎀 Parameters 🎀

  • group=name — name of the imagery group for ortho-rectification. i.e. which group of pics we're working with 🖼️
  • camera=name — required! name of the camera reference file. also the name of the input file. yes, mandatory, no skipsies 🫶
  • name=string — camera name. cute label for your cam 📸
  • id=string — camera id. the whole identity situation 💳
  • clf=float — calibrated focal length. the numbers, bestie 🔢
  • pp=east,north — principal point coordinates. these are coordinates 📍
  • fid=east,north[,east,north,...] — fiducial coordinates. also coordinates. you can stack a bunch of them like a lil list 💫

✨ DESCRIPTION ✨

okay so i.ortho.camera creates or modifies entries in a camera reference file. and for ortho-photo rectification, a camera reference file is required — like, non-negotiable — because it's what the computation of scanned image to photo-coordinate transformation parameters needs. periodt. 💅

there are two coordinate systems at play here:

  • the image coordinate system (in pixels) 📏
  • the photo coordinate system (in milli-meters) 📐

and the inner orientation is the thing that establishes a relation between the pixels and the image coordinates with help of fiducial marks. iykyk.

the first prompt in the program will ask you for the name of the camera reference file to be created or modified. you can:

  • create a new camera reference file by entering a new name, or
  • modify an existing camera reference file by entering the name of an existing camera file.

after entering the camera file name, this following menu is displayed:

Please provide the following information

    CAMERA NAME:               camera name______
    CAMERA IDENTIFICATION:     identification___
    CALIBRATED FOCAL LENGTH mm.:_________________
    POINT OF SYMMETRY (X)   mm.:_________________
    POINT OF SYMMETRY (Y)   mm.:_________________
    MAXIMUM NUMBER OF FIDUCIALS:_________________
   AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
               (OR <Ctrl-C> TO CANCEL)

the camera name and identification describe the camera reference file. the calibrated focal length and the point of symmetry are used in computing the photo-to-target transformation parameters. these values should be entered from the camera calibration report — which is usually available from the photograph supplier, so ask them bestie 🫶

this example is the camera Zeiss LMK9 265-002A belonging to the Hellenic Military Geographical Survey (HMGS) and calibrated in December 1985. iconic honestly. ✨

the photo coordinate system origin is the so-called calibrated principal point (PP, Principal Point of Symmetry) which is in the center of the image. the origin of the axes is at the intersection of the radii traced from the fiducial marks. in the ideal case of no deviations in the camera (see camera calibration certificate) the center is the origin and the values are 0 for both X and Y of Point of Symmetry. but — plot twist — usually the principal point does not fall on the intersection of the radii at the center of the picture. this eccentricity is usually of the order of a few micrometers. tiny but mighty 😭

you are then asked to enter the X and Y photo coordinates of each fiducial as follows. these fiducials (or reseau) marks are index marks imaged on film which serve as reference photo coordinate system. the maximum number of fiducials will determine the number of fiducial or reseau coordinate pairs to be entered below. the origin is the center of the image (or the point of symmetry) and X and Y are left-right and up-down. the order is up to the user, but it must be kept consistent throughout the rectification process. no switching it up mid-way, bestie 🚫

on this screen you should enter the fiducial or reseau photo-coordinates as given in the camera calibration report. the X, and Y coordinates are in milli-meters from the principle point.

Please provide the following information
    Fid#    FID ID          X          Y
    1__    _____        0.0___    0.0___
    2__    _____        0.0___    0.0___
    3__    _____        0.0___    0.0___
    4__    _____        0.0___    0.0___
    5__    _____        0.0___    0.0___
    6__    _____        0.0___    0.0___
    7__    _____        0.0___    0.0___
    8__    _____        0.0___    0.0___
    9__    _____        0.0___    0.0___
    10_    _____        0.0___    0.0___
            next:  end__
    AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE
                   (OR <Ctrl-C> TO CANCEL)

the input display is repeated until the number of MAXIMUM FIDUCIALS is reached. so yeah, it just keeps going. commitment. 🔁

lowkey important reminder: hit <ESC> to continue once you've completed all answers, or <Ctrl-C> to cancel. don't just sit there staring at it 💀

👀 SEE ALSO 👀

  • i.ortho.photo
  • g.gui.photo2image
  • g.gui.image2target
  • i.ortho.init

👑 AUTHOR 👑

Mike Baba, DBA Systems, Inc.

📦 SOURCE CODE 📦

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

Accessed: Saturday Jan 17 05:41:43 2026

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© 2003-2025 GRASS Development Team, GRASS GIS 8.4.2 Reference Manual

and that's the whole page, bestie!! 💖✨🎀🦋🌸💅🫶 you now know everything there is to know about i.ortho.camera, no cap.

okay so final sign-off: this was GRASS 8.4.2, and the manual was accessed Saturday Jan 17 05:41:43 2026 — © 2003-2025 GRASS Development Team. literally iconic, go orthorectify something gorgeous 🌈👑💜

📦 where this page comes from