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] [ddiirreecc--
       ttiioonn==_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 nomi-
	      nal distance.

       ddiirreeccttiioonn==_v_a_l_u_e
	      Direction  of  semivariogram. Default is omnidirec-
	      tional semivariogram.

       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  envi-
       ronment	variable  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
       written to _n_a_m_e.dat. Therefore, to replot a  sample  semi-
       variogram, use: ggnnuupplloott _n_a_m_e.gp

       To  plot a histogram of _N_(_h_), simply edit _n_a_m_e.gp and redo
       the previously 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)
