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



NNAAMMEE
       vv..eexxttrraacctt   - Selects vector objects from an existing vec-
       tor map and creates a new map containing only the selected
       objects.
       _(_S_C_S _G_R_A_S_S _V_e_c_t_o_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       vv..eexxttrraacctt
       vv..eexxttrraacctt hheellpp
       vv..eexxttrraacctt[[ --ddnn] ttyyppee==_n_a_m_e iinnppuutt==_n_a_m_e oouuttppuutt==_n_a_m_e nneeww==_v_a_l_u_e
       [lliisstt==_r_a_n_g_e] [ffiillee==_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       _v_._e_x_t_r_a_c_t allows a user to create a new vector  map  layer
       from an existing vector map layer.  User provides the pro-
       gram with category numbers or option (n) names, input vec-
       tor file name, an output vector file name, and the type of
       input object.  There is an option (d) to  dissolve  common
       boundaries  between  adjoining map areas in the same cate-
       gory list.  The user may specify a file	containing  cate-
       gory numbers or labels.


       Note:

	 The  dissolve option will work on only those areas which
       are in the
	      given  category  list.   If  a  map  area is inside
	      (island) a listed category area and is NOT  in  the
	      given  category  list, its boundaries are output to
	      the resultant map.

CCOOMMMMAANNDD LLIINNEE OOPPTTIIOONNSS
   FFllaaggss::
       --dd     Dissolve common boundaries (default is no) .

       --nn     Use category labels NOT category numbers.



   PPaarraammeetteerrss::
       ttyyppee==_n_a_m_e
	      Select area, area edge, line, or site.
	      Options:	area, edge, line, site

       iinnppuutt==_n_a_m_e
	      Input vector map name.

       oouuttppuutt==_n_a_m_e
	      Output vector map name.

       nneeww==_v_a_l_u_e
	      Enter 0 (keep original category) or a  desired  NEW
	      category number.

       lliisstt==_r_a_n_g_e
	      Category ranges.
	      For example:  1, 3-8, 13
	      For example:  Abc, Def2, XyZ

       ffiillee==_n_a_m_e
	      Text file name for category range/list .



EEXXAAMMPPLLEE
	vv..eexxttrraacctt --dd lliisstt==1,2,3,4
	      iinnppuutt==soils oouuttppuutt==soil_groupa ttyyppee==area nneeww==1


       Produces  a  new  vector  area file _s_o_i_l___g_r_o_u_p_a containing
       'area' boundaries from _s_o_i_l_s with area category numbers of
       1  thru	4;   any common boundaries are dissolved, and all
       areas of the new map will be assigned category number 1.



	vv..eexxttrraacctt --ddnn lliisstt==Abc,Def1,12A,WWd
	      iinnppuutt==soils oouuttppuutt==soil_groupa ttyyppee==area nneeww==0


       Produces a new vector  area  file  _s_o_i_l___g_r_o_u_p_a  containing
       'area'  boundaries from _s_o_i_l_s with area category labels of
       Abc,Def1, 12A,WWd; these labels correspond  to  numbers	1
       thru 4 of _s_o_i_l_s.  Any common boundaries are dissolved, all
       areas of the new map will be retain their  original  cate-
       gory  numbers 1 thru 4, in this case, since new was set to
       0.



	vv..eexxttrraacctt --nn iinnppuutt==soils oouuttppuutt==soil_groupa
	      ttyyppee==area nneeww==1 ffiillee==sample


       Produces a new vector  area  file  _s_o_i_l___g_r_o_u_p_a  containing
       'area'  boundaries  from  _s_o_i_l_s.  No common boundaries are
       dissolved, all areas of the new map will be assigned cate-
       gory  number  1.  The "labels" (-n option) can be found in
       the file sample of the current directory.

	The format for


       Abc
       Def1
       12A
       WWd


AAUUTTHHOORR
       R.L. Glenn, USDA, SCS, NHQ-CGIS



       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_4_/_1_3 _1_4_:_5_1_:_5_0 _$



GRASS 5.0					     v.extract(1)
