Note: A new GRASS GIS stable version has been released: GRASS GIS 7.8, available here.

Updated manual page: here

**-r**- Use initial values at run time
**-p**- Print initial values
**--help**- Print usage summary
**--verbose**- Verbose module output
**--quiet**- Quiet module output
**--ui**- Force launching GUI dialog

**group**=*name***[required]**- Name of imagery group for ortho-rectification
**xc**=*float*- Initial Camera Exposure X-coordinate
**yc**=*float*- Initial Camera Exposure Y-coordinate
**zc**=*float*- Initial Camera Exposure Z-coordinate
**xc_sd**=*float*- Apriori X-coordinate standard deviation
**yc_sd**=*float*- Apriori Y-coordinate standard deviation
**zc_sd**=*float*- Apriori Z-coordinate standard deviation
**omega**=*float*- Initial Camera Omega (roll) degrees
**phi**=*float*- Initial Camera Phi (pitch) degrees
**kappa**=*float*- Initial Camera Kappa (yaw) degrees
**omega_sd**=*float*- Apriori Omega (roll) standard deviation
**phi_sd**=*float*- Apriori Phi (pitch) standard deviation
**kappa_sd**=*float*- Apriori Kappa (yaw) standard deviation

Oblique aerial photographs are purposely taken with an angle between 3 and 90 degree from the nadir direction.

**The use of i.ortho.init (menu 6) is only required when rectifying a
tilted or oblique aerial photo.**

*i.ortho.init* creates or modifies entries in a camera initial exposure
station file for imagery group referenced by a sub-block. These entries
include: the (XC,YC,ZC) standard (e.g. UTM) approximate coordinates of the camera exposure
station; initial roll, pitch, and yaw angles (in degrees) of the cameras
attitude; and the *a priori* standard deviations for these
parameters. During the imagery program, *i.photo.rectify*, the initial camera
exposure station file is used for computation of the ortho-rectification
parameters. If no initial camera exposure station file exist, the default
values are computed from the control points file created in *i.photo.2target*.

The following menu is displayed:

Please provide the following information INITIAL XC: Meters __________ INITIAL YC: Meters __________ INITIAL ZC: Meters __________ INITIAL omega (roll) degrees: __________ INITIAL phi (pitch) degrees: __________ INITIAL kappa (yaw) degrees: __________ Standard Deviation XC: Meters __________ Standard Deviation YC: Meters __________ Standard Deviation ZC: Meters __________ Std. Dev. omega (roll) degrees: __________ Std. Dev. phi (pitch) degrees: __________ Std. Dev. kappa (yaw) degrees: __________ Use these values at run time? (1=yes, 0=no) AFTER COMPLETING ALL ANSWERS, HIT <ESC> TO CONTINUE (OR <Ctrl-C> TO CANCEL)

The INITIAL values for (XC,YC,ZC) are expressed in standard (e.g. UTM) coordinates, and represent an approximation for the location of the camera at the time of exposure.

- X: East aircraft position;
- Y: North aircraft position;
- Z: Flight altitude above sea level

The INITIAL values for (omega,phi,kappa) are expressed in degrees, and represent an approximation for the cameras attitude at the time of exposure.

- Omega (roll): Raising or lowering of the wings (turning around the aircraft's axis);
- Phi (pitch): Raising or lowering of the aircraft's front (turning around the wings' axis);
- Kappa (yaw): Rotation needed to align the aerial photo to true north: needs to be denoted as +90 degree for clockwise turn and -90 degree for a counterclockwise turn.

The standard deviations for (XC,YC,ZC) are expressed in meters, and
are used as *a priori* values for the standard deviations used in
computation of the ortho rectification parameters.

The standard deviations for (omega,phi,kappa) are expressed in degrees, and
are used as *a priori* values for the standard deviations used in
computation of the ortho rectification parameters.

If *Use these values at run time? (1=yes, 0=no)* is set to 0, the
values in this menu are not used.

*Last changed: $Date$*

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

Note: A new GRASS GIS stable version has been released: GRASS GIS 7.8, available here.

Updated manual page: here

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© 2003-2020 GRASS Development Team, GRASS GIS 7.6.2dev Reference Manual