s.sv(1) 		      Grass User's Manual		       s.sv(1)



NNAAMMEE
       ss..ssvv  - Sample semivariogram of a GRASS sites list.
       _(_G_R_A_S_S _S_i_t_e_s _P_r_o_g_r_a_m_)

SSYYNNOOPPSSIISS
       ss..ssvv
       ss..ssvv hheellpp
       ss..ssvv  [--aallqq]  [ssiitteess==_n_a_m_e]  llaagg==_v_a_l_u_e  [llaaggttooll==_v_a_l_u_e] [ddiirreeccttiioonn==_v_a_l_u_e]
       [aannggttooll==_v_a_l_u_e] [ggrraapphh==_n_a_m_e] [ffiieelldd==_v_a_l_u_e]]

DDEESSCCRRIIPPTTIIOONN
       _s_._s_v calculates a sample semivariogram and either plots it  using  _g_n_u_-
       _p_l_o_t or writes it to standard output.


       For more information, refer to the tutorial or see the example below.

OOPPTTIIOONNSS
   FFllaaggss::
       --qq     Quiet. Cut out the chatter.

       --pp     Plot the sample semivariogram (requires _g_n_u_p_l_o_t).

       ffiieelldd  Number of z-field attribute to use for calculation default: 1


   PPaarraammeetteerrss::
       ssiitteess==_n_a_m_e
	      Name  of	an existing sites file. Default is standard input with
	      no field separators.

       llaagg==_v_a_l_u_e
	      Nominal lag distance.

       llaaggttooll==_v_a_l_u_e
	      Tolerance on lag distance. Default is half of nominal  distance.

       ddiirreeccttiioonn==_v_a_l_u_e
	      Direction of semivariogram. Default is omnidirectional semivari-
	      ogram.

       aannggttooll==_v_a_l_u_e
	      Angular tolerance on direction.

       ggrraapphh==_n_a_m_e
	      Basename to save graphing data/commands files.  Graphs are saved
	      in  the  current	working  directory with the extensions _._g_p and
	      _._d_a_t. Implies the --pp  flag.  If  unspecified,  semivariogram  is
	      written to standard output.


NNOOTTEESS
       The  plotting  program can be selected by setting the environment vari-
       able GGRRAASSSS__GGNNUUPPLLOOTT .  Without the --pp flag, three columns  of  data  are
       written	to  standard  output:  lag  distance  (_h), semivariogram value
       (_g_a_m_m_a), and the number of data pairs used to compute it  (_N_(_h_)).  When
       the  ggrraapphh parameter is set, these same three columns of data are writ-
       ten to _n_a_m_e.dat. Therefore, to replot a sample semivariogram, use: ggnnuu--
       pplloott _n_a_m_e.gp

       To  plot  a  histogram of _N_(_h_), simply edit _n_a_m_e.gp and redo the previ-
       ously given command.


       For more information, refer to the tutorial.

SSEEEE AALLSSOO
       _s_._u_n_i_v_a_r

       _s_._s_u_r_f_._k_r_i_g

       _s_._n_o_r_m_a_l

       _m_._s_v_f_i_t

       _g_n_u_p_l_o_t
       _S_e_m_i_v_a_r_i_o_g_r_a_m _M_o_d_e_l_i_n_g  - A GRASS Tutorial on Exploratory Data Analysis
       and Semivariogram Modeling.

BBUUGGSS
       Will not work correctly with lat-long data.  Should _G___a_z_i_m_u_t_h_(_) be used
       to calculate the angle between points?


       Only Matheron's classical estimator is available with _s_._s_v.  Others may
       be added in the future.



AAUUTTHHOORR
       James Darrell McCauley, Agricultural Engineering, Purdue University

       _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							       s.sv(1)
