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 locations in an x,y
       coordinate system; etc.).

OOPPTTIIOONNSS
       The user can run this  program  either  non-interactively  or  interac-
       tively.	 The  program will be run non-interactively if the user speci-
       fies 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 command 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 direc-
       tory.


       _r_._l_i_n_e  maintains  the same format (binary or ASCII) and attribute type
       (linear or area edge) as those of the original 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)
