Chris
Could I be incredibly obvious and suggest that, if you
use Universal Kriging, the trend is fitted and
simulated automatically with SGS. This is one of the
major advantages of SGS over approaches like Turning
Bands or Monte-Carlo -- if you can krige it, you can
simulate it.
There is a lot of evidence in the literature, dating
back to the early '80s that kriging residuals and
adding back the trend gives you pretty much the same
estimated surface as Universal Kriging. However, what
it doesn't do is give you the right standard error
since it doesn't allow for the trend fitting error. So
I would hazard a guess that simulations done this way
would underestimate the 'true' variability.
Isobel {Clark}
http://drisobelclark.ontheweb.com
PS: could I take this opportunity to remind anyone
interested that the IAMG 2003 is rapidly approaching.
If you haven't registered yet, sort yourself out at
http://www.iamg2003.com or follow the links from our
page at http://ecosse.ontheweb.com/whatsnew.htm
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