NAME

       i.photo.init   -  Interactively creates or modifies entries in a camera initial exposure station file for
       imagery group referenced by a sub-block.

KEYWORDS

       imagery, orthorectify

SYNOPSIS

       i.photo.init
       i.photo.init help
       i.photo.init group=name  [--verbose]  [--quiet]

   Parameters:
       group=name
           Name of imagery group for ortho-rectification

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 vertical photograph up to a tilt of 3 degree.
       Oblique aerial photographs are purposely taken with an angle between 3  and  90  degree  from  the  nadir
       direction.

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

       i.photo.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 <A HREF="i.photo.2target.html">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.

SEE ALSO

        i.ortho.photo, i.photo.camera, i.photo.2image, i.photo.2target, i.photo.rectify

AUTHOR

       Mike Baba,  DBA Systems, Inc.

       Last changed: $Date: 2010-12-22 02:05:10 -0800 (Wed, 22 Dec 2010) $

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       © 2003-2013 GRASS Development Team