v.patch(1)	       Grass User's Manual	       v.patch(1)



NNAAMMEE
       vv..ppaattcchh	 -  Creates a new binary vector map layer by com-
       bining other binary vector map layers.
       _(_G_R_A_S_S _V_e_c_t_o_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       vv..ppaattcchh
       vv..ppaattcchh hheellpp
       vv..ppaattcchh iinnppuutt==_n_a_m_e[,_n_a_m_e,...]  oouuttppuutt==_n_a_m_e

DDEESSCCRRIIPPTTIIOONN
       _v_._p_a_t_c_h allows the user to combine any  number  of  vector
       map  layers  together  to  create one composite vector map
       layer.

OOPPTTIIOONNSS
   PPaarraammeetteerrss::
       iinnppuutt==_n_a_m_e,_n_a_m_e, ...
	      Name(s)  of  input  vector  map(s)  to  be  patched
	      together.

       oouuttppuutt==_n_a_m_e
	      Name  assigned to composite "patched" vector output
	      map.



       The program will be  run  non-interactively  if	the  user
       specifies the names of the vector map(s) to be patched and
       the name of an output file to store the resulting  compos-
       ite  patched  vector map on the command line, in the form:
       vv..ppaattcchh iinnppuutt==_n_a_m_e[,_n_a_m_e,...]  oouuttppuutt==_n_a_m_e



       Alternately, if the user runs _v_._p_a_t_c_h  without  specifying
       input and output file names on the command line (by typing
       simply vv..ppaattcchh), the program  will  prompt  the	user  for
       inputs using the standard GRASS interface described in the
       manual entry for _p_a_r_s_e_r.

NNOOTTEESS
       The vector map layers to be patched together must exist in
       the  user's  current mapset search path, and the composite
       vector map layer name given must not already exist in  the
       user's current mapset.


       After  running  _v_._p_a_t_c_h, the header file will contain only
       information taken from the first _i_n_p_u_t file name given  in
       the string iinnppuutt==_n_a_m_e_,_n_a_m_e_, _._._., with the exception of the
       geographic region's edge information, and  the  scale  and
       threshold  information.	 (The  user's  current geographic
       region settings are ignored; this information  is  instead
       extracted  from	the vector file headers.) In the new com-
       posite vector map layer, the boundaries of the  geographic
       region will be expanded to encompass all of the geographic
       area included in the map layers	being  patched,  and  the
       scale will be set equal to the smallest (i.e., most gross)
       scale used by any of the patched  map  layers  (this  will
       affect default node-snapping thresholds).  The map thresh-
       old is calculated automatically from the map scales  given
       in the file headers, and (currently) is not used directly.
       The composite vector map layer's header will probably need
       to  be edited; this can be done from within the GRASS pro-
       gram _v_._d_i_g_i_t.


       The GRASS programs _v_._m_k_g_r_i_d and _v_._m_k_q_u_a_d_s can be  used  to
       ensure that the borders of the maps to be patched together
       align neatly.


       Any vectors that  are  duplicated  among  the  maps  being
       patched	together  (e.g.,  border  lines)  will have to be
       edited or removed after _v_._p_a_t_c_h is run.	Such editing  can
       be done using _v_._d_i_g_i_t.


       After  running  _v_._p_a_t_c_h the user must run _v_._s_u_p_p_o_r_t on the
       composite vector map layer in order to create  a  dig_plus
       (topology)  file  for  it.   At this time, you can request
       that a _v_e_r_y small snapping threshold be used, to cause the
       nodes  that  match  up  across  vector  map layers to snap
       together without affecting the integrity of the	remainder
       of the vector map layer.

BBUUGGSS
       The  dig_cats  and reg file information for the maps being
       patched together is not copied to the  composite,  patched
       map layer.  The user should therefore run _v_._s_u_p_p_o_r_t on the
       output file produced by this program.

SSEEEE AALLSSOO
       _v_._d_i_g_i_t, _v_._i_n_._a_s_c_i_i, _v_._m_k_g_r_i_d, _v_._m_k_q_u_a_d_s,  _v_._s_u_p_p_o_r_t,  and
       _p_a_r_s_e_r

AAUUTTHHOORR
       Dave  Gerdes,  U.S.Army	Construction Engineering Research
       Laboratory

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_5 _$



GRASS 5.0					       v.patch(1)
