d.rhumbline(1)	       Grass User's Manual	   d.rhumbline(1)



NNAAMMEE
       dd..rrhhuummbblliinnee   -	Displays  the rhumbline joining two user-
       specified points, in the active frame on the user's graph-
       ics monitor.
       _(_G_R_A_S_S _D_i_s_p_l_a_y _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       dd..rrhhuummbblliinnee
       dd..rrhhuummbblliinnee hheellpp
       dd..rrhhuummbblliinnee ccoooorr==_l_o_n_1_,_l_a_t_1_,_l_o_n_2_,_l_a_t_2 [llccoolloorr==_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       A  rhumbline  is  a line following a constant angle of the
       compass (i.e., a line of constant direction).   There  are
       32 points on the compass (points are roughly 11 degrees 15
       minutes apart).	_d_._r_h_u_m_b_l_i_n_e displays the rhumbline  join-
       ing  any  two user-specified points in the active frame on
       the user's graphics monitor.  The named	coordinate  loca-
       tions  must  fall within the boundaries of the user's cur-
       rent geographic region.


       The user can run this program either interactively or non-
       interactively.	If  the  user simply types dd..rrhhuummbblliinnee on
       the command line without specifying parameter values,  the
       mouse  will be activated and the user will be asked to use
       the mouse to indicate the two endpoints of the  rhumbline.
       The  rhumbline is then drawn in the default color (white).
       The program also outputs the coordinate locations  of  the
       two  endpoints on the user's terminal and the number asso-
       ciated with the mouse button depressed by the  user  in	a
       format useful for input to other programs.


       Alternately,  the user can specify the starting and ending
       longitude/latitude  coordinates	of  the   rhumbline   and
       (optionally) the color in which the rhumbline will be dis-
       played; in this case, the program  will	run  non-interac-
       tively.

OOPPTTIIOONNSS
   PPaarraammeetteerrss::
       ccoooorr==_l_o_n_1_,_l_a_t_1_,_l_o_n_2_,_l_a_t_2
	      Starting	and  ending coordinates of the rhumblines
	      to be displayed, given as longitudes and latitudes.

       llccoolloorr==_n_a_m_e
	      Rhumbline color.
	      Options: red, orange, yellow, green, blue, magenta,
	      indigo, violet, gray, white, black
	      Default: white


NNOOTTEESS
       This  program  works  only  with  longitude-latitude  data
       bases.

SSEEEE AALLSSOO
       _d_._g_e_o_d_e_s_i_c

AAUUTTHHOORR
       Michael	 Shapiro,   U.S.  Army	Construction  Engineering
       Research Laboratory

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



GRASS 5.0					   d.rhumbline(1)
