v.what(1)	       Grass User's Manual		v.what(1)



NNAAMMEE
       vv..wwhhaatt  - Query the category contents of a (binary) vector
       map layer at user-selected locations.
       _(_G_R_A_S_S _V_e_c_t_o_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       vv..wwhhaatt
       vv..wwhhaatt hheellpp
       vv..wwhhaatt			[--11ii]			 mmaapp==_n_a_m_e
       [eeaasstt__nnoorrtthh==_e_a_s_t_,_n_o_r_t_h[,_e_a_s_t_,_n_o_r_t_h,...]

DDEESSCCRRIIPPTTIIOONN
       _v_._w_h_a_t outputs the category value(s) associated with user-
       specified location(s) in a vector map layer.

OOPPTTIIOONNSS
       If the --ii flag is specified,  the  program  activates  the
       mouse, and expects the user to indicate the location(s) to
       be queried by depressing a mouse button over desired loca-
       tion(s) within the current geographic region in the active
       display frame on the graphic monitor.


       If the --ii flag is not used, the program	expects  eastings
       and  northings to be entered from standard input.  In this
       case, input is terminated by typing Control-D.

   FFllaaggss::
       --11     Identify and query just one point location.

       --ii     Query interactively using mouse.


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

       eeaasstt__nnoorrtthh==
	      One or multiple coordinate pairs for query


EEXXAAMMPPLLEE
       Two sample _v_._w_h_a_t sessions are 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 for
       interactive queries.

       vv..wwhhaatt --ii 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 button.  The right button on the mouse is used
       to quit the _v_._w_h_a_t session.


       Users can also use this program inside of  shell  scripts.
       For example, if the file _c_o_o_r_d_s contains three UTM coordi-
       nates:

       599817.37 4922332.96
       593512.25 4917170.38
       604979.96 4921655.90


       ccaatt ccoooorrddss || vv..wwhhaatt mmaapp==_l_a_n_d_c_o_v_e_r

       will return information about these  three  locations  and
       then exit.

NNOOTTEESS
       _v_._w_h_a_t output can be redirected into a file.


       _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.


       _v_._w_h_a_t  was  created from _d_._w_h_a_t_._v_e_c_t so that non-interac-
       tively queries could be made. Specifying the --ii flag makes
       _v_._w_h_a_t behave just as _d_._w_h_a_t_._v_e_c_t does.

SSEEEE AALLSSOO
       _d_._v_e_c_t, _d_._w_h_a_t_._r_a_s_t, _d_._w_h_a_t_._v_e_c_t, _g_._r_e_g_i_o_n, and _p_a_r_s_e_r,

AAUUTTHHOORRSS
       Jim Hinthorn, Central Washington University, was the orig-
       inal author.
       Dennis Finch, National Park Service
       James Darrell McCauley, Agricultural  Engineering,  Purdue
       University

       added the non-interactive part and renamed to _v_._w_h_a_t

       _L_a_s_t _c_h_a_n_g_e_d_: _$_D_a_t_e_: _2_0_0_2_/_0_1_/_2_5 _0_5_:_4_5_:_3_5 _$



GRASS 5.0						v.what(1)
