I have a geostatistical data. For analysis, I am using `geoR`. I want to estimate the parameters. But `likfit` or `variofit` function requires initial values for the covariance parameters: [math]\sigma^2[/math] (partial sill) and [math]\phi[/math] (range parameter).

But I can't guess the initial values for my data set.

My data is in thousand (say, 3503.198, 1821.964, etc.) and coordinates are latitude and longitude. If I plug any values, it converges. But the estimates change. Say I put initial value [math]\sigma^2=1[/math] and [math]\phi=0.5[/math]. Then the estimated value of [math]\sigma^2=0[/math]. But if I plug [math]\sigma^2=22000[/math] and [math]\phi=0.5[/math], then the estimated value of [math]\sigma^2[/math] is a very big number.