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



NNAAMMEE
       vv..eexxttrraacctt   -  Selects  vector  objects from an existing vector 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[[ --dd] 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 exist-
       ing vector map layer.  User provides the program with category numbers,
       input  vector  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 category list.  The user may
       specify a file containing category 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 bound-
	      aries are output to the resultant map.

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



   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  num-
	      ber.

       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' bound-
       aries 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'	bound-
       aries  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
       category 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'	bound-
       aries from _s_o_i_l_s.  No common boundaries are dissolved, all areas of the
       new map will be assigned category number 1.  The "labels"  (-n  option)
       can be found in the file sample of the current directory.

	The format for


       Abc
       Def1
       12A
       WWd

	vv..eexxttrraacctt 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' bound-
       aries from _s_o_i_l_s.  No common boundaries are dissolved, all areas of the
       new  map  will be assigned category number 1.  The numbers can be found
       in the file sample of the current directory.

	The format for


       1
       33
       45
       56


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



       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_3_/_0_8_/_2_0 _0_8_:_1_0_:_1_3 _$



GRASS 5.0							  v.extract(1)
