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: \(\sigma^2\) (partial sill) and \(\phi\) (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 \(\sigma^2=1\) and \(\phi=0.5\). Then the estimated value of \(\sigma^2=0\). But if I plug \(\sigma^2=22000\) and \(\phi=0.5\), then the estimated value of \(\sigma^2\) is a very big number.