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



NNAAMMEE
       rr..llooss  - Line-of-sight raster analysis program.
       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       rr..llooss
       rr..llooss hheellpp
       rr..llooss	  iinnppuutt==_n_a_m_e	  oouuttppuutt==_n_a_m_e	   ccoooorrddiinnaattee==_x_,_y
       [ppaatttt__mmaapp==_n_a_m_e] [oobbss__eelleevv==_v_a_l_u_e] [mmaaxx__ddiisstt==_v_a_l_u_e]

DDEESSCCRRIIPPTTIIOONN
       _r_._l_o_s generates a raster map output  in	which  the  cells
       that  are  visible from a user-specified observer location
       are marked with integer values that represent the vertical
       angle (in degrees) required to see those cells (viewshed).


       The program can be run either non-interactively or  inter-
       actively.   To  run _r_._l_o_s non-interactively, the user must
       specify at least an iinnppuutt file name, oouuttppuutt file name, and
       the  geographic ccoooorrddiinnaattees of the user's viewing location
       on the command line; any remaining parameters whose values
       are  unspecified  on the command line will be set to their
       default values (see below).  Non-interactive usage  format
       is:    rr..llooss    iinnppuutt==_n_a_m_e    oouuttppuutt==_n_a_m_e   ccoooorrddiinnaattee==_x_,_y
       [ppaatttt__mmaapp==_n_a_m_e] [oobbss__eelleevv==_v_a_l_u_e] [mmaaxx__ddiisstt==_v_a_l_u_e]



       Alternately, the user can type simply rr..llooss on the command
       line;  in  this case, the program will prompt the user for
       parameter values using the standard GRASS _p_a_r_s_e_r.



   PPaarraammeetteerrss::
       iinnppuutt==_n_a_m_e
	      Name of a raster	map  layer  containing	elevation
	      data, used as program input.

       oouuttppuutt==_n_a_m_e
	      Name  assigned to the file in which the raster pro-
	      gram output will be stored.

       ccoooorrddiinnaattee==_x_,_y
	      Geographic coordinates (i.e., easting and  northing
	      values)  identifying  the  desired  location of the
	      viewing point.

       ppaatttt__mmaapp==_n_a_m_e
	      Name of a binary (1/0) raster map  layer	in  which
	      cells within the areas of interest are assigned the
	      category	value  '1',  and  all  other  cells   are
	      assigned	the category value '0'. If this parameter
	      is omitted, the analysis will be performed for  the
	      whole area within a certain distance of the viewing
	      point inside the geographic region boundaries.
	      Default: assign  all  cells  that  are  within  the
	      mmaaxx__ddiisstt	and  within the user's current geographic
	      region boundaries a value of 1.

       oobbss__eelleevv==_v_a_l_u_e
	      Height of the observer (in meters) above the  view-
	      ing point's elevation.
	      Default: 1.75 (meters)

       mmaaxx__ddiisstt==_v_a_l_u_e
	      Maximum distance (in meters) from the viewing point
	      inside of which the line of sight analysis will  be
	      performed.  The  cells  outside this distance range
	      are assigned the category value '0'.
	      Options: 0-99999 (stated in map units)
	      Default: 1000


NNOOTTEESS
       For accurate results, the program must  be  run	with  the
       resolution of the geographic region set equal to the reso-
       lution of the data (see _g_._r_e_g_i_o_n).


       It is advisable to use a 'pattern layer' which  identifies
       the  areas of interest in which the line of sight analysis
       is required.  Such a measure will reduce the time taken by
       the program to run.

SSEEEE AALLSSOO
       _g_._r_e_g_i_o_n
       _p_a_r_s_e_r

AAUUTTHHOORR
       Kewan  Q. Khawaja, Intelligent Engineering Systems Labora-
       tory, M.I.T.

       _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.los(1)
