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



NNAAMMEE
       vv..ttrriimm	-  Trims small spurs, and removes excessive nodes
       from a binary GRASS vector (_d_i_g) file.
       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       vv..ttrriimm
       vv..ttrriimm hheellpp
       vv..ttrriimm iinnppuutt==_n_a_m_e oouuttppuutt==_n_a_m_e [ttrriimm==_v_a_l_u_e]

DDEESSCCRRIIPPTTIIOONN
       _v_._t_r_i_m scans the user-specified GRASS  vector  iinnppuutt  file
       and  removes from it all lines having a length less than a
       user-specified  trimming  factor.   Excess  nodes   (those
       unnecessary to a line's definition) between line junctions
       are also removed.  The resulting vector output is sent  to
       a  user-named  oouuttppuutt file; the original vector iinnppuutt file
       is not modified by _v_._t_r_i_m.


       The trimming factor parameter (ttrriimm==_v_a_l_u_e) gives the  user
       control	over  the size of small spurs or "dangling lines"
       to be removed. The trimming factor  is  expressed  in  the
       same  units  (map  coordinates)	as  the vector (_d_i_g) data
       within the user's current GRASS data base LOCATION  (e.g.:
       in  meters for UTM locations; in pixels or cells for loca-
       tions in an x,y coordinate system; etc.).

OOPPTTIIOONNSS
       The user can run this program either non-interactively  or
       interactively.	The program will be run non-interactively
       if the user specifies program  arguments  on  the  command
       line,   using  the  form:  vv..ttrriimm  iinnppuutt==_n_a_m_e  oouuttppuutt==_n_a_m_e
       [ttrriimm==_v_a_l_u_e]

       If vector map iinnppuutt and oouuttppuutt names are given on the com-
       mand  line, any other parameter values left unspecified on
       the command line will be set to their default values  (see
       below).	 Alternately,  the user can simply type vv..ttrriimm on
       the command line, without program arguments. In this case,
       the  user  will	be  prompted  for needed parameter values
       using the standard GRASS _p_a_r_s_e_r interface.

   PPaarraammeetteerrss::
       iinnppuutt==_n_a_m_e
	      Name of an existing vector map layer in the  user's
	      current  mapset  search path containing lines to be
	      "trimmed".

       oouuttppuutt==_n_a_m_e
	      Name  of	a  new	vector	file  to  contained   the
	      "trimmed" output.

       ttrriimm==_v_a_l_u_e
	      A  user-specified  trimming  factor,  denoting  the
	      length of trimmed lines in map  units.   All  lines
	      having a length less than this trimming factor will
	      be "trimmed" (i.e., removed) from the named  vector
	      input file.
	      Default: 10 (in units of meters or cells)


NNOOTTEESS
       _v_._s_u_p_p_o_r_t  must	be  run on the vector iinnppuutt file prior to
       running _v_._t_r_i_m.


       _v_._s_u_p_p_o_r_t must also be run on the resultant vector  oouuttppuutt
       file to build the needed topology information stored under
       the user's _d_i_g___p_l_u_s directory.


       _r_._l_i_n_e maintains the same format  (binary  or  ASCII)  and
       attribute type (linear or area edge) as those of the orig-
       inal vector (_d_i_g) iinnppuutt file.


       A trimming factor of zero (0) will not  remove  any  small
       spurs, but will remove all excess nodes.

SSEEEE AALLSSOO
       _v_._d_i_g_i_t

       _v_._i_m_p_o_r_t

       _v_._s_u_p_p_o_r_t

       _p_a_r_s_e_r

AAUUTTHHOORR
       Mike Baba
       DBA Systems, Inc.

       _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.trim(1)
