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 tran-
       sect:  average  outputs	the average category value of all
       cells along the transect; median outputs the median  cate-
       gory 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 geographic 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 distance (_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 num-
       ber  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 aver-
       age 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 converts 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)
