.TH i.ortho.init 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBi.ortho.init\fR\fR  \- Interactively creates or modifies entries in a camera initial exposure station file for imagery group referenced by a sub\-block.
.SH KEYWORDS
imagery, orthorectify
.SH SYNOPSIS
\fBi.ortho.init\fR
.br
\fBi.ortho.init \-\-help\fR
.br
\fBi.ortho.init\fR [\-\fBrp\fR] \fBgroup\fR=\fIname\fR  [\fBxc\fR=\fIfloat\fR]   [\fByc\fR=\fIfloat\fR]   [\fBzc\fR=\fIfloat\fR]   [\fBxc_sd\fR=\fIfloat\fR]   [\fByc_sd\fR=\fIfloat\fR]   [\fBzc_sd\fR=\fIfloat\fR]   [\fBomega\fR=\fIfloat\fR]   [\fBphi\fR=\fIfloat\fR]   [\fBkappa\fR=\fIfloat\fR]   [\fBomega_sd\fR=\fIfloat\fR]   [\fBphi_sd\fR=\fIfloat\fR]   [\fBkappa_sd\fR=\fIfloat\fR]   [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-r\fR" 4m
.br
Use initial values at run time
.IP "\fB\-p\fR" 4m
.br
Print initial values
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBgroup\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of imagery group for ortho\-rectification
.IP "\fBxc\fR=\fIfloat\fR" 4m
.br
Initial Camera Exposure X\-coordinate
.IP "\fByc\fR=\fIfloat\fR" 4m
.br
Initial Camera Exposure Y\-coordinate
.IP "\fBzc\fR=\fIfloat\fR" 4m
.br
Initial Camera Exposure Z\-coordinate
.IP "\fBxc_sd\fR=\fIfloat\fR" 4m
.br
Apriori X\-coordinate standard deviation
.IP "\fByc_sd\fR=\fIfloat\fR" 4m
.br
Apriori Y\-coordinate standard deviation
.IP "\fBzc_sd\fR=\fIfloat\fR" 4m
.br
Apriori Z\-coordinate standard deviation
.IP "\fBomega\fR=\fIfloat\fR" 4m
.br
Initial Camera Omega (roll) degrees
.IP "\fBphi\fR=\fIfloat\fR" 4m
.br
Initial Camera Phi (pitch) degrees
.IP "\fBkappa\fR=\fIfloat\fR" 4m
.br
Initial Camera Kappa (yaw) degrees
.IP "\fBomega_sd\fR=\fIfloat\fR" 4m
.br
Apriori Omega (roll) standard deviation
.IP "\fBphi_sd\fR=\fIfloat\fR" 4m
.br
Apriori Phi (pitch) standard deviation
.IP "\fBkappa_sd\fR=\fIfloat\fR" 4m
.br
Apriori Kappa (yaw) standard deviation
.SH DESCRIPTION
Aerial photographs may be either vertical or oblique. Vertical photographs
can be truly vertical (nadir), or slightly tilted (less than 3 degree
from the vertical). Usually aerial photos are tilted to some degree. We
refer to the term \fIvertical photograph\fR up to a tilt of 3 degree.
.br
Oblique aerial photographs are purposely taken with an
angle between 3 and 90 degree from the nadir direction.
.PP
\fBThe use of \fIi.ortho.init\fR (menu 6) is only required when rectifying a
tilted or oblique aerial photo.\fR
.PP
\fIi.ortho.init\fR 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 \fIa priori\fR standard deviations for these
parameters. During the imagery program, \fIi.photo.rectify\fR, 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 \fIi.photo.2target\fR.
.PP
The following menu is displayed:
.br
.nf
\fC
        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)
\fR
.fi
.PP
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.
.RS 4n
.IP \(bu 4n
X: East aircraft position;
.IP \(bu 4n
Y: North aircraft position;
.IP \(bu 4n
Z: Flight altitude above sea level
.RE
.PP
The INITIAL values for (omega,phi,kappa) are expressed in degrees, and
represent an approximation for the cameras attitude  at the time of
exposure.
.RS 4n
.IP \(bu 4n
Omega (roll): Raising or lowering of the wings (turning around the
aircraft\(cqs axis);
.IP \(bu 4n
Phi (pitch): Raising or lowering of the aircraft\(cqs front (turning
around the wings\(cq axis);
.IP \(bu 4n
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.
.RE
.PP
The standard deviations for (XC,YC,ZC) are expressed in meters, and
are used as \fIa priori\fR values for the standard deviations used in
computation of the ortho rectification parameters.
.PP
The standard deviations for (omega,phi,kappa) are expressed in degrees, and
are used as \fIa priori\fR values for the standard deviations used in
computation of the ortho rectification parameters.
.PP
If \fIUse these values at run time? (1=yes, 0=no)\fR is set to 0, the
values in this menu are not used.
.SH SEE ALSO
\fI
i.ortho.photo,
i.photo.2image,
i.photo.2target,
i.ortho.elev,
i.ortho.camera,
i.ortho.transform,
i.photo.rectify
\fR
.SH AUTHOR
Mike Baba,  DBA Systems, Inc.
.SH SOURCE CODE
.PP
Available at: i.ortho.init source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual