Re: defining dummy data

[Ashton Shortridge]

Data gets upset and sulks when you insult it with nasty names.... ;)

I am unsure of what you are trying to do. What is your ultimate objective? I'm 
guessing that you are trying to simulate a random field unconditionally using 
your variogram model - is that right? If so, and I'm not an expert at Gstat, 
I think you need to tell Gstat where the data object is coming from, ie:
data(Pox.STONE): 'mygridfile.asc';
or, if by 'dummy' you mean that there is no data file, I think you need to 
specify that:
data(Pox.STONE): dummy, <other arguments>;

See Example 6 in the manual.

Ashton

On Friday 08 August 2003 06:04, Ulrich Leopold wrote:
> Dear list,
>
> I try to define dummy data in a command file but I always get the
> message following error message:
>
> ----------------------------------------------------------
> gstat: Linux version 2.4.2 (26 April 2003)
> Copyright (C) 1992, 2003 Edzer J. Pebesma
> using Marsaglia's random number generator
> gstat: value not allowed for: cannot determine coordinate mode of data
> data(Pox.STONE):
> ----------------------------------------------------------
>
> MY COMMAND FILE LOOKS LIKE THE FOLLOWING:
> -----------------------------------------------------------
> #
> # gstat command file, Linux version 2.4.2 (26 April 2003)
> # Thu Aug  7 18:30:00 2003
> #
> data(Pox.STONE);
>
> variogram(Pox.STONE): 'Pox.STONE.est';
> variogram(Pox.STONE): 42.8068 Nug(0) + 34.7856 Exp(673.291) + 12.7951
> Sph(11420.
> 2) + 29.3024 Sph(59234.6);
> -----------------------------------------------------------
>
> THIS IS THE VARIOGRAM FILE:
> -----------------------------------------------------------
> #gstat Linux 2.4.2 (26 April 2003) [gstat-2.4.2 Pox.STONE.cmd]
> #sample semivariogram
> #Thu Aug  7 18:29:40 2003
> #data(Pox.STONE): '250.Pox.STONE.0t30cm';
> #[1] mean: 13.6699 variance: 109.677
> #cutoff: 60000 interval width: 250
> #direction: total
> #   from       to  n_pairs  av_dist semivariogram
>        0      250   823894      250  52.7086
>      250      500  1611332  426.245  61.5305
> ------------------------------------------------------------
>
> Any suggestions what is going wrong? Maybe it has to do with the
> variogram file? I used a grid file as data input.
>
> Regards, Ulrich

-- 
Ashton Shortridge
Assistant Professor                     [EMAIL PROTECTED]
Dept of Geography                       http://www.msu.edu/~ashton
Michigan State University               (517) 432-3561