d.rast.arrow(1) 	      Grass User's Manual	       d.rast.arrow(1)



NNAAMMEE
       dd..rraasstt..aarrrrooww   -  Draws arrows representing cell aspect direction for a
       raster map layer.
       _(_G_R_A_S_S _D_i_s_p_l_a_y _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       dd..rraasstt..aarrrrooww
       dd..rraasstt..aarrrrooww hheellpp
       dd..rraasstt..aarrrrooww	 [mmaapp==_n_a_m_e]	  [ttyyppee==_n_a_m_e]	    [aarrrrooww__ccoolloorr==_n_a_m_e]
       [ggrriidd__ccoolloorr==_n_a_m_e] [xx__ccoolloorr==_n_a_m_e] [uunnkknnoowwnn__ccoolloorr==_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       _d_._r_a_s_t_._a_r_r_o_w  is  designed to help users better visualize surface water
       flow direction, as indicated in an aspect raster map layer.  There  are
       two  ways to specify the aspect layer the program is to use.  The first
       is to display the aspect map layer on the graphics monitor before  run-
       ning  _d_._r_a_s_t_._a_r_r_o_w.  The second method involves setting the _m_a_p parame-
       ter to the name of the desired aspect map.  This allows the  arrows  to
       be drawn over any other maps already displayed on the graphics monitor.


       _d_._r_a_s_t_._a_r_r_o_w will draw an arrow over each displayed cell to indicate in
       which  direction  the  cell slopes.  An arrow can point in one of eight
       directions.  If the aspect layer has a category	value  denoting  loca-
       tions  of "unknown" aspect, _d_._r_a_s_t_._a_r_r_o_w draws a question mark over the
       displayed cells of that category.  Cells of category 0 (no  data)  will
       be marked with an "X".


	NNoottee::	Arrows	are  cell size and cannot be seen if the raster map is
       relatively close in scale.  From a command line mode, the  user	cannot
       run  _d_._r_a_s_t_._a_r_r_o_w  and  then  run _d_._z_o_o_m and still see the arrows.  The
       zooming action erases the arrows and the  user  must  run  _d_._r_a_s_t_._a_r_r_o_w
       again.

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

       ttyyppee==_n_a_m_e
	      Type of existing raster data to be displayed.
	      Options:	grass, agnps, answers
	      Default:	grass
	      Using  this  information, _d_._r_a_s_t_._a_r_r_o_w uses internal information
	      to convert category values into appropriate arrow directions.

       aarrrrooww__ccoolloorr==_n_a_m_e
	      Color in which arrows will be drawn.
	      Options:	white, red, orange, yellow, green, blue, indigo,  vio-
	      let, magenta, brown, gray, black
	      Default:	green

       ggrriidd__ccoolloorr==_n_a_m_e
	      Color in which grid outlines will be drawn.
	      Options:	 white, red, orange, yellow, green, blue, indigo, vio-
	      let, magenta, brown, gray, black
	      Default:	gray

       xx__ccoolloorr==_n_a_m_e
	      Color in which x's will be drawn.
	      Options:	white, red, orange, yellow, green, blue, indigo,  vio-
	      let, magenta, brown, gray, black
	      Default:	white

       uunnkknnoowwnn__ccoolloorr==_n_a_m_e
	      Color in which unknown information will be displayed.
	      Options:	 white, red, orange, yellow, green, blue, indigo, vio-
	      let, magenta, brown, gray, black
	      Default:	red


SSEEEE AALLSSOO
       _d_._f_r_a_m_e

       _d_._r_a_s_t

       _d_._r_a_s_t_._e_d_i_t

       _d_._r_a_s_t_._n_u_m

       _d_._z_o_o_m

       _g_._r_e_g_i_o_n

       _r_._m_a_s_k

       _r_._s_l_o_p_e_._a_s_p_e_c_t

       _p_a_r_s_e_r

AAUUTTHHOORR
       Chris Rewerts, Agricultural Engineering, Purdue University

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_3 _$



GRASS 5.0						       d.rast.arrow(1)
