Specifying the initial values of likfit function of geodata in R

#1
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.

How can I specify the initial values?
 

Dason

Ambassador to the humans
#2
Are you saying you don't know any value to plug in or you've tried some values and it doesn't end up converging?
 
#3
Are you saying you don't know any value to plug in or you've tried some values and it doesn't end up converging?
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.