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



NNAAMMEE
       rr..ggrrooww	-  Generates an output raster map layer with con-
       tiguous areas grown by one cell (pixel).
       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       rr..ggrrooww
       rr..ggrrooww hheellpp
       rr..ggrrooww [--bbqq] iinnppuutt==_n_a_m_e oouuttppuutt==_n_a_m_e

DDEESSCCRRIIPPTTIIOONN
       _r_._g_r_o_w adds one cell around the perimeters of all areas in
       a user-specified raster map layer and stores the output in
       a new raster map layer.


       An area consists of any contiguous  clump  of  cells  with
       non-zero  category  values. No distinction is made between
       differing category values within an area. Rather, a border
       is  grown around the outside of each entire contiguous set
       of non-zero cells.


       The oouuttppuutt raster map layer will not go outside the bound-
       aries  set  in  the current geographic region.  Thus, if a
       contiguous area in the iinnppuutt raster map layer  extends  to
       the  geographic edge of the current map layer, no new bor-
       der cells can be added to that side of the area.


       Growth around a rectangular area in the iinnppuutt  raster  map
       layer  will  occur  straight  out  from each edge, but not
       diagonally from the corners of the  rectangle.  Thus,  the
       "grown"	border	area will contain lines along the edge of
       the original rectangle, but the corners of the border will
       not  be	squared  off.	Instead,  the lines of the border
       which go along each side of the	original  rectangle  will
       touch  only at the corners of the cells at the end of each
       line.

OOPPTTIIOONNSS
       The user can run _r_._g_r_o_w either interactively or non-inter-
       actively.   The	program  is run interactively if the user
       types rr..ggrrooww without specifying flag settings and  parame-
       ter  values  on	the command line.  In this case, the user
       will be prompted for input.


       Alternately, the user can run _r_._g_r_o_w non-interactively, by
       specifying the names of an iinnppuutt and oouuttppuutt map layer, and
       including any desired flags, on the command line.



   FFllaaggss::
       --bb     Output a binary raster map layer having only  zero-
	      one  category  values,  regardless  of the category
	      values in the iinnppuutt map layer.  In this  case,  all
	      cells  with  a non-zero category value in the iinnppuutt
	      map layer are assigned to category 1 in the  oouuttppuutt
	      map layer.  If the -b flag is not used, these cells
	      will  retain  their  original   non-zero	 category
	      values.  In  either  case, all cells whose category
	      value is changed from 0 during the growing  process
	      are  assigned  a	category value of 1 in the oouuttppuutt
	      map.

       --qq     Run quietly,  supressing	printing  of  information
	      about program progress to standard output.




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

       oouuttppuutt==_n_a_m_e
	      Name of the new raster map layer to contain program
	      output.  This map will be binary if the  user  sets
	      the -b flag. Otherwise, iinnppuutt map cells having non-
	      zero category values  will  retain  their  original
	      values.	In  either  case,  all cells whose values
	      changed during growth  will  be  assigned  category
	      value 1 in the oouuttppuutt map.


NNOOTTEESS
       The  _r_._g_r_o_w  command can be used to represent the boundary
       of one or more areas. In this case, the zero-one  (binary)
       output option should NOT be used. Then the iinnppuutt map layer
       can be subtracted from the  oouuttppuutt  map	layer  using  the
       _r_._m_a_p_c_a_l_c  command.  All original non-zero category values
       will be subtracted out, leaving the boundary  areas  only.
       This  resulting	zero-one  boundary  depiction can be dis-
       played over other related  raster  map  layers  using  the
       overlay option of _d_._r_a_s_t.


       If  the	resolution  of the current geographic region does
       not agree with the resolution  of  the  input  raster  map
       layer,  unintended  resampling  of the original raster map
       layer may occur.  The user should be sure that the current
       geographic region is set properly.

SSEEEE AALLSSOO
       _d_._r_a_s_t

       _g_._r_e_g_i_o_n

       _r_._m_a_p_c_a_l_c

       _r_._p_o_l_y

AAUUTTHHOORR
       Marjorie   Larson,   U.S.  Army	Construction  Engineering
       Research Laboratory

       _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.grow(1)
