r.contour(1)	       Grass User's Manual	     r.contour(1)



NNAAMMEE
       _r_._c_o_n_t_o_u_r  -  Produces a GRASS binary vector map of speci-
       fied contours from GRASS raster map layer.

       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       rr..ccoonnttoouurr

       rr..ccoonnttoouurr hheellpp

       rr..ccoonnttoouurr    [[--qqnn]]    iinnppuutt==_n_a_m_e     oouuttppuutt==_n_a_m_e     [lleevv--
       eellss==_v_a_l_u_e,_v_a_l_u_e,...,_v_a_l_u_e]		 [mmiinnlleevveell==_v_a_l_u_e]
       [mmaaxxlleevveell==_v_a_l_u_e] [sstteepp==_v_a_l_u_e] [ccuutt==_v_a_l_u_e]

DDEESSCCRRIIPPTTIIOONN
       _r_._c_o_n_t_o_u_r produces a contour map of user-specified  levels
       from a raster map layer. This program works two ways:

	      Contours are produced from a user-specified list of
	      levels.

	      Contours are produced  at  some  regular	increment
	      from user-specified minimum level to maximum level.
	      If no minimum or maximum level is specified,  mini-
	      mum or maximum data value will be used.


OOPPTTIIOONNSS
       _r_._c_o_n_t_o_u_r  may  be run interactively or non-interactively.
       To run the program non-interactively, the user must  spec-
       ify the input and output file names, either a list of lev-
       els or a step value and, optionally, minimum  and  maximum
       levels:	 rr..ccoonnttoouurr  [[--qqnn]]  iinnppuutt==_n_a_m_e  oouuttppuutt==_n_a_m_e  [lleevv--
       eellss==_v_a_l_u_e,_v_a_l_u_e,...,_v_a_l_u_e]		 [mmiinnlleevveell==_v_a_l_u_e]
       [mmaaxxlleevveell==_v_a_l_u_e] [sstteepp==_v_a_l_u_e] [ccuutt==_v_a_l_u_e]

       To run the program interactively, the user may simply type
       rr..ccoonnttoouurr at the command line and  will	be  prompted  for
       parameter values.



   FFllaaggss::
       --qq   Suppress progress report & min/max information

       --nn   Suppress single crossing error messages

   PPaarraammeetteerrss::
       iinnppuutt==_n_a_m_e
	   Name of input raster map layer.

       oouuttppuutt==_n_a_m_e
	   Name of the binary vector file created.

       lleevveellss==_v_a_l_u_e,_v_a_l_u_e,...,_v_a_l_u_e
	   Comma separated list of desired levels.

       mmiinnlleevveell==_v_a_l_u_e
	   Beginning  (lowest)	value  to  be  used when stepping
	   through contours. Default is minimum data value.

       mmaaxxlleevveell==_v_a_l_u_e
	   Ending  (highest)  value  to  be  used  when  stepping
	   through contours. Default is maximum data value.

       sstteepp==_v_a_l_u_e
	   Increment between contour levels.

       ccuutt==_v_a_l_u_e
	   Minimum  number  of points for a contour line (0 -> no
	   limit, default: 0)


NNOOTTEESS
       _r_._c_o_n_t_o_u_r will either step through incremental contours or
       produce	contours from a list of levels, not both. If both
       a list of levels and a step are specified, the  list  will
       be produced and the step will be ignored.

       Zero is treated as a valid data value by _r_._c_o_n_t_o_u_r.

       If a contour level exactly matches a category value in the
       raster file, the contour line  may  backtrack  on  itself,
       causing	illegal  arcs  to be produced in the output GRASS
       vector file.

       The optional _c_u_t parameter allows  to  specify  a  minimum
       number  of  point for a contour line to be put into output
       vector map, so that small spurs, single points and  so  on
       won't be present and the output will be more clear.

AAUUTTHHOORRSS
       Terry  Baker,  U.S. Army Construction Engineering Research
       Laboratory

       3/2001:	cut  parameter	 and   fixes   by   Andrea   Aime
       (aaime@libero.it)

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_4 _$



GRASS 5.0					     r.contour(1)
