[R-sig-Geo] Huge kriging weights when using kriging with external drift in gstat

[Tobias Vetter]

Thank you.
So as long as all my distances   are smaller than the range I will not 
have this problem?
Tobias
> Tobias, try using another variogram model: the linear model with sill is
> not positive definite in more than one dimension (and yes: a warning
> about this would have been very nice!)
>
> On 07/02/2013 03:37 PM, Tobias Vetter wrote:
>> Dear  all,
>> I am interpolating automatically  daily air temperature values using
>> kriging with external drift (altitude) and the library gstat. From time
>> to time (quite random) I get unrealistic predictions like -400°C with
>> very high kriging weights   like 2000.
>>   Looking at the data everything seems to be ok.  Then I changed the
>> variogram ranges  a little bit and the problem disappears.
>> How can this behavior be explained?
>>
>>   I  have attached a small  example script for demonstration  and some data.
>>
>> Thanks you
>> Tobias
>>
>>
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