v.in.poly(1)	       Grass User's Manual	     v.in.poly(1)



NNAAMMEE
       vv..iinn..ppoollyy   - Create a vector file of polygons centered on
       given locations
       _(_G_R_A_S_S _V_e_c_t_o_r _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       vv..iinn..ppoollyy
       vv..iinn..ppoollyy hheellpp
       vv..iinn..ppoollyy [ --tt] [iinnppuutt==_n_a_m_e] vveecctt==_n_a_m_e rraaddiiuuss==_v_a_l_u_e  [sseegg--
       mmeennttss==_v_a_l_u_e]

DDEESSCCRRIIPPTTIIOONN
       This program creates a vector map of polygons of specified
       radius around center points which may be input as  coordi-
       nate pairs from a file or from stdin.

CCOOMMMMAANNDD LLIINNEE OOPPTTIIOONNSS
       FFllaaggss



       --tt     Do not automatically build topology for the new map


       PPaarraammeetteerrss



       iinnppuutt==_n_a_m_e
	      Name of input file (omit or use -  for  input  from
	      stdin)
	      default: - (stdin)

       vveecctt==_n_a_m_e
	      Name of new vector map to create

       rraaddiiuuss==_v_a_l_u_e
	      Radius of polygon's circumscribed circle
	      default: none

       sseeggmmeennttss==_v_a_l_u_e
	      Number of straight line segments bounding the poly-
	      gon
	      default: set to give  perimeter  point  spacing  of
	      0.02%  of  the width of the current region based on
	      the radius given.  The smallest number of  segments
	      that  will be automatically used is six(6).  Values
	      down to 3 may be explicitly selected on the command
	      line  or	in input lines (see below).  A value of 3
	      results in an equilateral  triangle,  4  a  square,
	      etc.



DDIISSCCUUSSSSIIOONN AANNDD AADDDDIITTIIOONNAALL IINNPPUUTT LLIINNEE PPAARRAAMMEETTEERRSS
       If  input  is  from a keyboard, a prompt will be given for
       each input line.  The input lines from the file	or  stdin
       should look like this:


	 easting northing [label] [category desc]
		     or
	 easting northing [#label] [category desc]


       The   "#label"	for  is  for  center  points  piped  from
       s.out.ascii, like this:

	 ss..oouutt..aasscciiii  --dd   sitefile  |	 vv..iinn..ppoollyy   vveecctt==newvect
       rraaddiiuuss==500

       The  polygon  (area)  label  and  category description are
       optional.  "label" is an integer and the  "category  desc"
       is  any	text  string.  If the label value is missing, the
       label value used is one greater	than  the  last  and  the
       description is "n-sided polygon," where n is the number of
       bounding segments.  In this way a series  of  sequentially
       numbered  polygons may be created by just giving the east-
       ing and northing center coordinates.


       Two optional command lines may be  interspersed	with  the
       input  lines  containing the coordinate and optional label
       and category descriptions.  These lines begin with ".S" or
       ".R".   Note the restrictions on values of radius and seg-
       ments parameters below.


	.S 500


       Changes the number of straight line segments  which  bound
       the  polygon  to  a new value.  With large values (greater
       than 20) the polygons will approximate circles.	The mini-
       mum  value of 3 will create an equilateral triangle.  Very
       large values are allowed, but the resulting "circles"  may
       have  more definition than is needed and will take lots of
       storage space for the vector map.


	.R 100


       Changes the radius of the circle to a new  value.   Radius
       must  be  greater than 0.0; however, very small values may
       give meaningless circles and v.support may not be able  to
       construct  the topology if the points on the perimeter are
       too closely spaced.



BBUUGGSS
       Circles	in  Lat-Long  locations  are  not  really  round.
       Really  large  Lat-Long circles or polygons may look oddly
       misshappen when displayed.



SSEEEE AALLSSOO
       _v_._t_o_._r_a_s_t can be used to convert the  polygons  to  raster
       maps for masking, etc.



AAUUTTHHOORR
       Dr. James R. Hinthorne, GIS Laboratory, Central Washington
       University.  April 1992.

       _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.in.poly(1)
