photo.init(1)		      Grass User's Manual		 photo.init(1)



_T_h_i_s _i_s _n_o_t _a _c_o_m_m_a_n_d _i_t_s_e_l_f_, _b_u_t _a_n _o_p_t_i_o_n _o_f _t_h_e _c_o_m_m_a_n_d _i_._o_r_t_h_o_._p_h_o_t_o_.

NNAAMMEE
       _p_h_o_t_o_._i_n_i_t  - An imagery function that creates or modifies the optional
       entries in a camera initial exposure station file for an imagery group.
       _(_G_R_A_S_S _I_m_a_g_e _P_r_o_c_e_s_s_i_n_g _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       Selected from _i_._o_r_t_h_o_._p_h_o_t_o

DDEESSCCRRIIPPTTIIOONN
       Aerial  photographs  may be either vertical or oblique. Vertical photo-
       graphs 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 _v_e_r_t_i_c_a_l _p_h_o_t_o_g_r_a_p_h 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.


       TThhee uussee ooff _p_h_o_t_o_._i_n_i_t (menu 6)  is  only  required  when  rectifying  a
       tilted or oblique aerial photo.


       _p_h_o_t_o_._i_n_i_t  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) positional (e.g. UTM) approximate coor-
       dinates of the camera exposure station; initial roll,  pitch,  and  yaw
       angles  (in degrees) of the cameras attitude; and the _a _p_r_i_o_r_i standard
       deviations  for	these  parameters.   During   the   imagery   program,
       photo.rectify,  the  initial  camera  exposure station file is used for
       computation of the ortho-rectification parameters.  If no initial  cam-
       era  exposure  station file exist, the default values are computed from
       the control points file created in _p_h_o_t_o_._2_t_a_r_g_e_t .


       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:   __________

	    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 _p_r_i_o_r_i 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 _p_r_i_o_r_i values for the	standard  deviations  used  in
       computation of the ortho rectification parameters.


       If  _U_s_e _t_h_e_s_e _v_a_l_u_e_s _a_t _r_u_n _t_i_m_e_? _(_1_=_y_e_s_, _0_=_n_o_) is set to 0, the values
       in this menu are not used.

SSEEEE AALLSSOO
	_i_._o_r_t_h_o_._p_h_o_t_o
	_p_h_o_t_o_._c_a_m_e_r_a

	_p_h_o_t_o_._2_i_m_a_g_e

	_p_h_o_t_o_._2_t_a_r_g_e_t

	_p_h_o_t_o_._r_e_c_t_i_f_y



AAUUTTHHOORR
       Mike Baba,  DBA Systems, Inc.

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_3_/_0_9_/_0_9 _1_3_:_1_0_:_1_8 _$



GRASS 5.0							 photo.init(1)
