Thanks for your advice, all. I downloaded the Surfer 8 demo software and found that Surfer 8's results are much closer to mine than Surfer 6. This, Mr. McCarn's recollection, and a cursory look at Surfer 6's memory usage during processing all indicate that Surfer 6 uses 4-byte floating point arithmetic, even though Golden Software tech support claims otherwise.
I wish I could nail down why my results are still different than Surfer 8 by up to 5%. I think it is probably floating point error that accumulates over the many calculations required to solve for Kriging weights, so I plan to look at some numerical methods books and do some testing etc. If you have experience with floating-point problems and would like to share, I'm all ears! Eva -----Original Message----- From: Bambang Trisasongko [mailto:[EMAIL PROTECTED]] Sent: Wednesday, February 20, 2002 2:58 AM To: Eva Pierce Cc: [EMAIL PROTECTED] Subject: Re: AI-GEOSTATS: Surfer 6.04 Hi Eva, I usually saw the problem in remote sensing image analysis. From my experience, the difference is based on different use of floating point data types. As you may refer on standard textbook on programming languages, there are slightly difference between languages in handling floating point data. Another problem is coding mathematical/statistical equations. Solving equations may be constructed in different ways. I usually refer to some numerical analysis book such as John Rice, Don Knuth or if you using specific programming languages, there are versions of Numerical Recipes by Press et al. I hope it can help. Regards, Bambang -- * To post a message to the list, send it to [EMAIL PROTECTED] * As a general service to the users, please remember to post a summary of any useful responses to your questions. * To unsubscribe, send an email to [EMAIL PROTECTED] with no subject and "unsubscribe ai-geostats" followed by "end" on the next line in the message body. DO NOT SEND Subscribe/Unsubscribe requests to the list * Support to the list is provided at http://www.ai-geostats.org
