d.what.vect(1)	       Grass User's Manual	   d.what.vect(1)



NNAAMMEE
       dd..wwhhaatt..vveecctt  -  Allows the user to interactively query the
       category contents of a (binary) vector map layer at  user-
       selected locations within the current geographic region.
       _(_G_R_A_S_S _D_i_s_p_l_a_y _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       dd..wwhhaatt..vveecctt
       dd..wwhhaatt..vveecctt hheellpp
       dd..wwhhaatt..vveecctt [--11tt] mmaapp==_n_a_m_e [ttaabbllee==_n_a_m_e] [kkeeyy==_n_a_m_e]

DDEESSCCRRIIPPTTIIOONN
       _d_._w_h_a_t_._v_e_c_t  outputs the category value(s) associated with
       user-specified location(s) in a user-specified vector  map
       layer. This program currently returns only category values
       for line types in the user-specified vector file.


       The program will query the  contents  of  the  vector  map
       layer  named  by  the  user  on the command line. This map
       layer must exist in the user's current mapset search path.


       The  program  activates the mouse, and expects the user to
       indicate the location(s) to be  queried	by  depressing	a
       mouse  button  over desired location(s) within the current
       geographic region in  the  active  display  frame  on  the
       graphic monitor.


       Alternatively  user can specify ttaabbllee== and kkeeyy== and window
       with database attributes will be opened for each  selected
       object with assigned category.

   FFllaagg::
       --11     Identify	and  query  just one point location. Only
	      one mouse click is executed. This  option  is  pro-
	      vided  for  shell scripts and programs that want to
	      obtain only one point from the user.

       --tt     Provide only terse output. This option is  provided
	      to  simplify  the  parsing  of output by other pro-
	      grams. Database connection must be set up by d.con-
	      nect first.


   PPaarraammeetteerr::
       mmaapp==_n_a_m_e
	      Name of an existing binary vector map in the user's
	      mapset search path.

       ttaabbllee==_n_a_m_e
	      Name of database table containing attributes.

       kkeeyy==_n_a_m_e
	      Name of database table key (id) column.


EEXXAAMMPPLLEE
       A sample _d_._w_h_a_t_._v_e_c_t session is given below.  Although  it
       is  not necessary that the user first display a vector map
       to be queried in the active display frame, it  is  helpful
       to have a map displayed there for reference.



       dd..vveecctt mmaapp==_r_o_a_d_s_._2_4_0_0_0
	      Displays	the 1:24,000 scale _r_o_a_d_s vector map layer
	      on the graphics monitor.


       dd..wwhhaatt..vveecctt mmaapp==_r_o_a_d_s_._2_4_0_0_0 After typing  this,	the  user
       moves  the  mouse  to  a desired location on the displayed
       _r_o_a_d_s map layer, and presses  the  left	mouse  button  to
       query  the  category value of the _r_o_a_d_s vector map at this
       location. The program then outputs the category value of a
       line  type  corresponding  to this user-selected map loca-
       tion, for the vector map queried by the user.


       The query may be repeated as often as  desired  using  the
       left  mouse button.  The right button on the mouse is used
       to quit the _d_._w_h_a_t_._v_e_c_t session.


       Users can also use this program inside  of  shell  scripts
       that  require  as  input  a map category value and a mouse
       button depressed.  Users  can  set  the	-1  flag  to  run
       _d_._w_h_a_t_._v_e_c_t  only  once,  and return only the map category
       value found and the number of the mouse button  depressed.
       (Mouse button return values are as follows: 0 indicates no
       button was pressed, 1 indicates that the left mouse button
       was  pressed,  2  indicates the middle button was pressed,
       and 3 indicates that the right mouse button was	pressed.)

NNOOTTEESS
       Currently,  _d_._w_h_a_t_._v_e_c_t	only  outputs category values for
       lines.  It does not output category labels for lines,  nor
       output  category  values or category labels for areas in a
       vector file.


       _d_._w_h_a_t_._v_e_c_t will always print its  output  to  the  user's
       terminal  screen.   _d_._w_h_a_t_._v_e_c_t	output	can be redirected
       into a file; however, if it is, the output will go both to
       the  screen  and  to  the  file.  For example: dd..wwhhaatt..vveecctt
       mmaapp==_r_o_a_d_s >> wwhhaatt..oouutt

       will both send _d_._w_h_a_t_._v_e_c_t output to the screen	and  cap-
       ture its output in the file named _w_h_a_t_._o_u_t.


       _d_._w_h_a_t_._r_a_s_t  can  be  used  to interactively query the map
       category contents of multiple raster map layers	at  user-
       selected locations.

SSEEEE AALLSSOO
       _d_._r_a_s_t

       _d_._v_e_c_t

       _d_._w_h_a_t_._r_a_s_t

       _g_._r_e_g_i_o_n

       _d_b_._c_o_n_n_e_c_t

       _p_a_r_s_e_r

AAUUTTHHOORR
       Jim Hinthorne, Central Washington University
       Upgrades: Dennis Finch, National Park Service



GRASS 5.0					   d.what.vect(1)
