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 interactively.  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 program output
	      will be stored.

       ccoooorrddiinnaattee==_x_,_y
	      Geographic coordinates (i.e., easting and northing values) iden-
	      tifying 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  viewing  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 resolution 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 mea-
       sure 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 Laboratory, 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)
