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



NNAAMMEE
       rr..mmeeddiiaann   -  Finds  the  median  of values in a cover map
       within areas assigned the same category value in  a  user-
       specified base map.
       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       rr..mmeeddiiaann
       rr..mmeeddiiaann hheellpp
       rr..mmeeddiiaann bbaassee==_n_a_m_e ccoovveerr==_n_a_m_e oouuttppuutt==_n_a_m_e

DDEESSCCRRIIPPTTIIOONN
       _r_._m_e_d_i_a_n  calculates the median category of data contained
       in a ccoovveerr raster map layer for areas  assigned	the  same
       category  value	in  the  user-specified  bbaassee  raster map
       layer.  These median values are stored in the  new  oouuttppuutt
       map layer.


       The oouuttppuutt map is actually a _r_e_c_l_a_s_s of the bbaassee map.

OOPPTTIIOONNSS
       If the user simply types rr..mmeeddiiaann on the command line, the
       user is prompted for  the  parameter  values  through  the
       standard _p_a_r_s_e_r interface.


       Alternately, the user can supply all needed parameter val-
       ues on the command line.

   PPaarraammeetteerrss::
       bbaassee==_n_a_m_e
	      An existing raster map layer in the user's  current
	      mapset  search  path.   For  each  group	of  cells
	      assigned the same category value in the  bbaassee  map,
	      the  median  of  the values assigned these cells in
	      the ccoovveerr map will be computed.

       ccoovveerr==_n_a_m_e
	      An existing raster map layer containing the  values
	      to  be used to compute the median within each cate-
	      gory of the bbaassee map.

       oouuttppuutt==_n_a_m_e
	      The name of a new map layer to contain program out-
	      put (a _r_e_c_l_a_s_s of the bbaassee map).	The median values
	      will be stored in the oouuttppuutt map.


NNOOTTEESS
       The user should use the results	of  _r_._m_e_d_i_a_n  with  care.
       Since  this  utility assigns a value to each cell which is
       based on global information (i.e., information at  spatial
       locations  other  than  just  the  location  of	the  cell
       itself), the resultant map layer is only valid if the geo-
       graphic region and mask settings are the same as they were
       at the time that the result map was created.


       Results are affected by the current  region  settings  and
       mask.

SSEEEE AALLSSOO
       _g_._r_e_g_i_o_n  _r_._a_v_e_r_a_g_e  _r_._c_a_t_s  _r_._c_l_u_m_p  _r_._d_e_s_c_r_i_b_e _r_._m_a_p_c_a_l_c
       _r_._m_a_s_k  _r_._m_f_i_l_t_e_r  _r_._m_o_d_e  _r_._n_e_i_g_h_b_o_r_s  _r_._r_e_c_l_a_s_s  _r_._s_t_a_t_s
       _p_a_r_s_e_r

AAUUTTHHOORR
       Michael	 Shapiro,   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.median(1)
