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



NNAAMMEE
       rr..ccrroossss	 - Creates a cross product of the category values
       from multiple raster map layers.
       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       rr..ccrroossss
       rr..ccrroossss hheellpp
       rr..ccrroossss [--qqzz] iinnppuutt==_n_a_m_e_,_n_a_m_e[,_n_a_m_e,...] oouuttppuutt==_n_a_m_e

DDEESSCCRRIIPPTTIIOONN
       _r_._c_r_o_s_s creates an _o_u_t_p_u_t raster  map  layer  representing
       all  unique  combinations of category values in the raster
       input layers (input=_n_a_m_e_,_n_a_m_e_,_n_a_m_e, ...).  At  least  two,
       but not more than ten, _i_n_p_u_t map layers must be specified.
       The user must also specify a name to be	assigned  to  the
       _o_u_t_p_u_t raster map layer created by _r_._c_r_o_s_s.

OOPPTTIIOONNSS
       The  program  will  be  run  non-interactively if the user
       specifies the names of between 2-10 raster map  layers  be
       used  as _i_n_p_u_t, and the name of a raster map layer to hold
       program	 _o_u_t_p_u_t,   using   the	 form:	 rr..ccrroossss    [--qqzz]
       iinnppuutt==_n_a_m_e_,_n_a_m_e[,_n_a_m_e,...] oouuttppuutt==_n_a_m_e

       where  each  input _n_a_m_e specifies the name of a raster map
       layer to be used in calculating	the  cross  product,  the
       output  _n_a_m_e  specifies	the name of a raster map layer to
       hold program output, and the options  --qq  and  --zz  respec-
       tively  specify	that  the  program  is to run quietly and
       exclude zero data values.


       Alternately, the user can simply type rr..ccrroossss on the  com-
       mand  line,  without  program arguments. In this case, the
       user will be prompted for  needed  input  and  output  map
       names  and  flag  settings using the standard GRASS parser
       interface.



   FFllaaggss::
       --qq     Run quietly. Supresses output of	program  percent-
	      complete messages.  If this flag is not used, these
	      messages are printed out.

       --zz     Do not cross zero data values.  This means that  if
	      a  zero  category  value	occurs	in any input data
	      layer, the combination is assigned to category zero
	      in the resulting map layer, even if other data lay-
	      ers contain non-zero data.  In  the  example  given
	      above,  use  of  the  --zz option would cause 3 cate-
	      gories to be generated instead of 5.


       If the --zz flag is not specified, then map  layer  combina-
       tions  in  which  not all category values are zero will be
       assigned a unique category  value  in  the  resulting  map
       layer.




   PPaarraammeetteerrss::
       iinnppuutt==_n_a_m_e_,_n_a_m_e[,_n_a_m_e,...]
	      The  names  of  between two and ten existing raster
	      map layers to be used as input.  Category values in
	      the  new _o_u_t_p_u_t map layer will be the cross-product
	      of the category values from  these  existing  _i_n_p_u_t
	      map layers.

       oouuttppuutt==_n_a_m_e
	      The  name assigned to the new raster map layer cre-
	      ated by _r_._c_r_o_s_s, containing program output.


EEXXAAMMPPLLEE
       For example, suppose that, using two  raster  map  layers,
       the following combinations occur:

		 map1	map2
		 ___________
		  0	 1
		  0	 2
		  1	 1
		  1	 2
		  2	 4

       _r_._c_r_o_s_s	would produce a new raster map layer with 5 cate-
       gories:

		 map1	map2   output
		 ____________________
		  0	 1	 1
		  0	 2	 2
		  1	 1	 3
		  1	 2	 4
		  2	 4	 5

       Note: The actual category value assigned to  a  particular
       combination  in	the  _r_e_s_u_l_t map layer is dependent on the
       order in which the combinations occur  in  the  input  map
       layer  data and can be considered essentially random.  The
       example given here is illustrative only.

SSUUPPPPOORRTT FFIILLEESS
       The category file created for the _o_u_t_p_u_t raster map  layer
       describes  the  combinations  of  input map layer category
       values which generated each category.  In the above  exam-
       ple, the category labels would be:

		 category   category
		 value	    label
		 ______________________________
		    1	    layer1(0) layer2(1)
		    2	    layer1(0) layer2(2)
		    3	    layer1(1) layer2(1)
		    4	    layer1(1) layer2(2)
		    5	    layer1(2) layer2(4)

       A  random color table is also generated for the _o_u_t_p_u_t map
       layer.

NNOOTTEESS
       When  run  non-interactively,  _r_._c_r_o_s_s  will  not  protect
       existing files in the user's mapset. If the user specifies
       an _o_u_t_p_u_t file name that already exists in his mapset, the
       existing  file  will  be  overwritten  by  the new _r_._c_r_o_s_s
       output.

SSEEEE AALLSSOO
       _r_._c_o_v_a_r

       _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.cross(1)
