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



NNAAMMEE
       vv..ppaattcchh	 -  Creates  a	new binary vector map layer by combining 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  composite  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 out-
       put file names on the command line (by typing simply vv..ppaattcchh), the pro-
       gram 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  composite
       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 threshold 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 program _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 vec-
       tor 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 pro-
       gram.

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)
