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



NNAAMMEE
       dd..wwhhaatt..vveecctt  - Allows the user to interactively query the category con-
       tents 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-speci-
       fied location(s) in a user-specified vector  map  layer.  This  program
       currently returns only category values for line types in the user-spec-
       ified 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  cate-
       gory.

   FFllaagg::
       --11     Identify and query just one point location. Only one mouse click
	      is executed. This option is provided for shell scripts and  pro-
	      grams 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  programs.  Database  connection
	      must be set up by db.connect 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	neces-
       sary  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 graph-
	      ics 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 location, for  the	vector
       map queried by the user.


       The query may be repeated as often as desired using the left mouse but-
       ton.  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 cate-
       gory 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 capture 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  con-
       tents 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)
