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



NNAAMMEE
       rr..ddiissttaannccee  -  Locates the closest points between objects in two raster
       maps.

       (GRASS Raster Program)

SSYYNNOOPPSSIISS
       rr..ddiissttaannccee

       rr..ddiissttaannccee hheellpp

       rr..ddiissttaannccee [[--llqq]] mmaappss_=_m_a_p_1_,_m_a_p_2 [ffss_=_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       Locates the closest points between "objects" in two  raster  maps.   An
       "object"  is  defined as all the grid cells that have the same category
       number, and closest means having the shortest "straight-line" distance.


       The output is an ascii list, one line per pair of objects

		  cat1:cat2:distance:east1:north1:east2:north2


   EExxppllaannaattiioonn::
       ccaatt11   Category number from map1

       ccaatt22   Category number from map2

       ddiissttaannccee
	      The distance in meters between "cat1" and "cat2"

       eeaasstt11,,nnoorrtthh11
	      The  coordinates	of  the  grid  cell "cat1" which is closest to
	      "cat2"

       eeaasstt22,,nnoorrtthh22
	      The coordinates of the grid cell	"cat2"	which  is  closest  to
	      "cat1"


CCOOMMMMAANNDD LLIINNEE OOPPTTIIOONNSS
   FFllaaggss::
       --ll     Include category labels in the output

       --qq     Run quietly


   PPaarraammeetteerrss::
       mmaappss   Maps for computing inter-class distances

       ffss     Output field separator Default is a colon (:)


NNOOTTEESS
       The  output  format  lends  itself to filtering.  For example, to "see"
       lines connecting each of the category pairs in  two  maps,  filter  the
       output using awk and then into _d_._m_a_p graph:


       _r_._d_i_s_t_a_n_c_e _m_a_p_s_=_m_a_p_1_,_m_a_p_2 _| _a_w_k _-_F_: _'_{_p_r_i_n_t _"_m_o_v_e_"_,_$_4_,_$_5_,_"_d_r_a_w_"_,_$_6_,_$_7_}_'
       _| _d_._m_a_p_g_r_a_p_h


       To create a site list of all the "map1" coordinates, filter the	output
       into awk and then into _s_._i_n_._a_s_c_i_i:


       _r_._d_i_s_t_a_n_c_e  _m_a_p_s_=_m_a_p_1_,_m_a_p_2  _|  _a_w_k  _-_F_:	_'_{_p_r_i_n_t  _$_4_,_$_5_}_'  _| _s_._i_n_._a_s_c_i_i
       _s_i_t_e_s_=_n_a_m_e

SSEEEE AALLSSOO
       _r_._d_r_a_i_n

AAUUTTHHOORR
       Michael Shapiro, U.S. Army Construction Engineering Research Laboratory

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_1_2_/_1_1 _1_8_:_0_0_:_4_3 _$



GRASS 5.0							 r.distance(1)
