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



NNAAMMEE
       rr..ttrraannsseecctt   - Outputs raster map layer values lying along user defined
       transect line(s).
       _(_G_R_A_S_S _R_a_s_t_e_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       rr..ttrraannsseecctt
       rr..ttrraannsseecctt hheellpp
       rr..ttrraannsseecctt	  mmaapp==_n_a_m_e	   [rreessuulltt==_t_y_p_e]	 [wwiiddtthh==_v_a_l_u_e]
       lliinnee==_e_a_s_t_,_n_o_r_t_h_,_a_z_i_m_u_t_h_,_d_i_s_t_a_n_c_e[_,_e_a_s_t_,_n_o_r_t_h_,_a_z_i_m_u_t_h_,_d_i_s_t_a_n_c_e_,_._._.]

DDEESSCCRRIIPPTTIIOONN
       This  progream  outputs, in ASCII, the values in a raster map which lie
       along one or more  user-defined	transect  lines.   The	transects  are
       described  by  their  starting coordinates, azimuth, and distance.  The
       transects may be single-cell wide lines, or multiple-cell  wide	lines.
       The  output, for each transect, may be the values at each of the cells,
       or a single aggregate value (e.g., average or median value).

OOPPTTIIOONNSS
   PPaarraammeetteerrss::
       mmaapp==_n_a_m_e
	      Name of an existing raster map layer to be queried.

       rreessuulltt==_t_y_p_e
	      Type of results to be output.
	      Options: raw, median, average
	      Default: raw


       If raw results are output, each of  the	category  values  assigned  to
       cells  falling  along  the  transect  are  output.   Median and average
       results output a single value per transect: average outputs the average
       category  value	of  all  cells	along the transect; median outputs the
       median category value of these cells.

       lliinnee=_e_a_s_t_,_n_o_r_t_h_,_a_z_i_m_u_t_h_,_d_i_s_t_a_n_c_e[_,_e_a_s_t_,_n_o_r_t_h_,_a_z_i_m_u_t_h_,_d_i_s_t_a_n_c_e_,_._._.]
	      A definition of (each) transect  line,  specified  by  the  geo-
	      graphic  coordinates  of its starting point (_e_a_s_t_i_n_g_, _n_o_r_t_h_i_n_g),
	      the angle and direction of its travel (_a_z_i_m_u_t_h),	and  its  dis-
	      tance (_d_i_s_t_a_n_c_e).


       The  _a_z_i_m_u_t_h  is  an  angle, in degrees, measured to the east of north.
       The _d_i_s_t_a_n_c_e is in map units (meters for a metered database, like UTM).

       wwiiddtthh==_v_a_l_u_e
	      Profile width, in cells (odd number).
	      Default: 1


       Wider  transects can be specified by setting the width to 3, 5, 7, etc.
       The transects are then formed as rectangles 3, 5, 7, etc., cells  wide.


OOUUTTPPUUTT FFOORRMMAATT
       The  output  from  this command is printed to standard output in ASCII.
       The format of the output varies	slightly  depending  on  the  type  of
       result  requested.   The  first	number	printed is the number of cells
       associated with the transect.  For raw output, this number is  followed
       by  the	individual  cell  values.  For average and median output, this
       number is followed by a single value (i.e., the average or  the	median
       value).


       The  following  examples  use the _e_l_e_v_a_t_i_o_n_._d_e_m raster map layer in the
       _s_p_e_a_r_f_i_s_h sample data set distributed with GRASS  4.0.	(To  reproduce
       these examples, first set the geographic region as shown:


       gg..rreeggiioonn rraasstt==_e_l_e_v_a_t_i_o_n_._d_e_m



       Single-cell transect:
	      rr..ttrraannsseecctt mmaapp==_e_l_e_v_a_t_i_o_n_._d_e_m lliinnee==_5_9_3_6_5_5_,_4_9_1_7_2_8_0_,_4_5_,_1_0_0


       4 1540 1551 1557 1550



       3-cell wide transect:
	      rr..ttrraannsseecctt mmaapp==_e_l_e_v_a_t_i_o_n_._d_e_m lliinnee==_5_9_3_6_5_5_,_4_9_1_7_2_8_0_,_4_5_,_1_0_0 wwiiddtthh==_3


       22 1556 1538 1525 1570 1555 1540 1528 1578 1565
       1551 1536 1523 1569 1557 1546 1533 1559 1550 1542
       1552 1543 1548
       (Output appears as multiple lines here, but is really one line)



       3-cell wide transect average:
	      rr..ttrraannsseecctt  mmaapp==_e_l_e_v_a_t_i_o_n_._d_e_m lliinnee==_5_9_3_6_5_5_,_4_9_1_7_2_8_0_,_4_5_,_1_0_0 wwiiddtthh==_3
	      rreessuulltt==_a_v_e_r_a_g_e


       22 1548.363636



       3-cell wide transect median:
	      rr..ttrraannsseecctt mmaapp==_e_l_e_v_a_t_i_o_n_._d_e_m lliinnee==_5_9_3_6_5_5_,_4_9_1_7_2_8_0_,_4_5_,_1_0_0  wwiiddtthh==_3
	      rreessuulltt==_m_e_d_i_a_n


       22 1549.000000


NNOOTTEESS
       This  program  is a front-end to the _r_._p_r_o_f_i_l_e program.	It simply con-
       verts the azimuth and distance to an ending coordinate  and  then  runs
       _r_._p_r_o_f_i_l_e.

SSEEEE AALLSSOO
       _r_._p_r_o_f_i_l_e


       _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.transect(1)
