fields                package:fields                R Documentation

_f_i_e_l_d_s - _t_o_o_l_s _f_o_r _s_p_a_t_i_a_l _d_a_t_a

_D_e_s_c_r_i_p_t_i_o_n:

     Fields is a collection of programs for curve and function fitting
     with an emphasis on spatial data and spatial statistics. The major
     methods implemented include cubic and thin plate splines,
     universal Kriging and Kriging for large data sets. One main
     feature is any covariance function implemented in R can be used
     for spatial prediction. 

     Some major methods include:

        *  'Tps'   Thin Plate spline regression (including GCV) 

        *  'Krig'  Spatial process estimation (Kriging) 

        *  'krig.image'   Spatial process estimate for large problems

     The Kriging functions allow you to supply a covariance function
     that is written in native S/R code. The Matern family
     ('Matern.cov') is  included as a built in  covariance. 

     Some other noteworthy functions are

        *  'cover.design'  Space-filling designs where the distance 
           function is expresed in R/S code

        *  'as.image'    'image.plot'   'image.count' 'smooth.image' 
           convenient functions  for working with image data

        *  'sreg',  'qsreg' 'splint'   Fast 1-D smoothing  splines and
           1-D  quantile/robust and interpolating cubic splines

     There are also generic functions that support  these methods such
     as 

     'plot' - diagnostic plots of fit 
      'summary'- statistical summary of fit 
      'print'- shorter version of summary 
      'surface'- graphical display of fitted surface 
      'predict'- evaluation fit at arbitrary points 
      'predict.se'- prediction standard errors at arbitrary points. 
      'sim.rf'- Simulate a random fields on a 2-d grid.

     To get started, try some of the examples from help files for 'Tps'
     or  'Krig'. See also the manual/tutorial at  <URL:
     http://www.cgd.ucar.edu/stats/Software/fields>

     DISCLAIMER:

     This is software for statistical research and not for commercial
     uses. The authors do not guarantee the correctness of any function
     or program in this package. Any changes to the software should not
     be made without the authors permission.

_E_x_a_m_p_l_e_s:

     set.panel()
     fit<- Tps(ozone$x, ozone$y)  # fits a thin plate spline surface to ozone 
     #                               measurements.
     summary(fit) #summary of the fit 
     plot(fit) # diagnostic plots of  fit and residuals.
     surface( fit, type="I") # image and contour plot of the fitted surface

