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Re: [Sgems-users] How Do I Start to Use Sgems
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From: David R. <dar...@ya...> - 2009-02-18 21:14:43
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You need to have your data in the GSLIB format in a .DAT file format. Then you drag it from file explorer and drop it into the big black viewing window in SGEMS. D. David A Robinson Snr Lecturer, Tropical Soil Processes and Ecohydrology Dept of Food Production University of the West Indies St Augustine Trinidad and Tobago West Indies Web: http://uwisoils.googlepages.com/home --- On Wed, 2/18/09, ubulom ubulom <ubu...@ya...> wrote: From: ubulom ubulom <ubu...@ya...> Subject: Re: [Sgems-users] How Do I Start to Use Sgems To: sge...@li... Date: Wednesday, February 18, 2009, 2:22 AM Dear List, I found the Sgems software quite suitable for my academic research need. My main problem is how to LOAD DATA. I am trying to model subsurface sandstone and shale intercalation reservoir facies. Moreover, I need to model reservoir petrophysical properties, like porosity, saturations and permeabilities. My available data set include porosity, permeability, and saturation values. Facies information include, sand thickness, shale and silt thicknesses. For each of the zones, I have coordinates. Please I have not used no seen neither the GSLIB format ot GEMS Binary data format. How do you help me with examples to allow me load these data and try to carry out kriging and Sequential Gaussian Simulation. Kindly help me to start. Thanks. Ubulom Ubulom --- On Tue, 2/17/09, sge...@li... <sge...@li...> wrote: From: sge...@li... <sge...@li...> Subject: Sgems-users Digest, Vol 29, Issue 5 To: sge...@li... Date: Tuesday, February 17, 2009, 10:52 AM Send Sgems-users mailing list submissions to sge...@li... To subscribe or unsubscribe via the World Wide Web, visit https://lists.sourceforge.net/lists/listinfo/sgems-users or, via email, send a message with subject or body 'help' to sge...@li... You can reach the person managing the list at sge...@li... When replying, please edit your Subject line so it is more specific than "Re: Contents of Sgems-users digest..." Today's Topics: 1. Re: Exponential model in sgems (Pierre Goovaerts) 2. Re: MultiGaussian Kriging (Pierre Goovaerts) 3. Periodic sgsim (Ben Scandella) ---------------------------------------------------------------------- Message: 1 Date: Tue, 17 Feb 2009 08:47:57 -0500 From: Pierre Goovaerts <goo...@te...> Subject: Re: [Sgems-users] Exponential model in sgems To: sara sabri <sar...@ya...> Cc: sge...@li... Message-ID: <775...@ma...> Content-Type: text/plain; charset="iso-8859-1" Dear Sara, The practical range of the exponential model in S-GeMS corresponds to what is called the "effective" range in Gslib. The choice of indicator kriging versus multiGaussian kriging depends on several factors, and the shape of the histogram might not be the critical one. Factors include the existence of a large proportion of observations with the same value (e.g. data below the detection limit), or the asymmetry in the spatial continuity of low and high values. In all situations, cross-validation could help deciding which method to adopt.. These last few months I have been involved with the modeling of contaminated sediments at several sites and multiGaussian kriging was adopted based on cross-validation results. Also, I recently published a paper in Computers & Geosciences and the associated computer code that implements all the steps of indicator kriging, including the modeling of all indicator variograms & cross-validation/jack-knife with generation of accuracy plots, automatically. Regards, Pierre On Tue, Feb 17, 2009 at 6:00 AM, sara sabri <sar...@ya...> wrote: > Dear list > waht is the range of an exponential model in s-gems? i.e. practical range > should be used? Is it the same with GSLIB? > And finally with a data of relatively normal distribution which methods > should I use to model the conditional probability? Is SISIM justified? Or I > have to use it only in case of asymetric distribution of categorical > variable? > I really appreiate your comments. > Thanks in advance > Sara > > ------------------------------ > New Email addresses available on Yahoo! > <http://sg.rd.yahoo.com/aa/mail/domainchoice/mail/signature/*http://mail.promotions.yahoo.com/newdomains/aa/> > Get the Email name you've always wanted on the new @ymail and @rocketmail. > Hurry before someone else does! > > > ------------------------------------------------------------------------------ > Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, > CA > -OSBC tackles the biggest issue in open source: Open Sourcing the > Enterprise > -Strategies to boost innovation and cut costs with open source > participation > -Receive a $600 discount off the registration fee with the source code: > SFAD > http://p.sf.net/sfu/XcvMzF8H > _______________________________________________ > Sgems-users mailing list > Sge...@li... > https://lists.sourceforge.net/lists/listinfo/sgems-users > > -- Pierre Goovaerts Chief Scientist at BioMedware Inc. 516 North State Street Ann Arbor, MI 48104 Voice: (734) 913-1098 (ext. 8) Fax: (734) 913-2201 Courtesy Associate Professor, University of Florida Geostatistician, Computer Sciences Corporation President, PGeostat LLC 710 Ridgemont Lane Ann Arbor, MI 48103 Voice: (734) 668-9900 Fax: (734) 668-7788 http://goovaerts.pierre.googlepages.com/ -------------- next part -------------- An HTML attachment was scrubbed... ------------------------------ Message: 2 Date: Tue, 17 Feb 2009 08:59:35 -0500 From: Pierre Goovaerts <goo...@te...> Subject: Re: [Sgems-users] MultiGaussian Kriging To: sara sabri <sar...@ya...> Cc: sge...@li... Message-ID: <775...@ma...> Content-Type: text/plain; charset="iso-8859-1" Dear Sara, The back-transform of estimated normal scores is not trivial and simply applying a normal score back-transform to kriging estimates will yield biased estimates. It's analogous to taking the exponent of lognormal kriging estimates, it won't do the trick... Besides, you cannot back-transform the kriging variance that way... I have explained the methodology to do the back-transform in a few papers, such as Goovaerts, P., AvRuskin, G., Meliker, J., Slotnick, M., Jacquez, G.M., and J. Nriagu. 2005. Geostatistical modeling of the spatial variability of arsenic in groundwater of Southeast Michigan. Water Resources Research, *41 *(7), W07013 10.102. Saito, H. and P. Goovaerts. 2000. Geostatistical interpolation of positively skewed and censored data in a dioxin contaminated site. Environmental Science & Technology, *34*(19): 4228-4235. Both papers can be downloaded from my webpage. The back-transform is done automatically in the beta version of a geostat GIS software I am developing at BioMedware, yet it works only in 2D. For the 3D modeling of contaminated sediments I mentioned in a previous e-mail, I am using my own code... The other option, easier yet more CPU-intensive, is to use sgsim and compute the E-type estimates of all back-transformed simulated values using postsim. The results should in theory be similar to multiGaussian kriging, assuming the number of realizations is large enough and you get the kriging variance as well. Pierre On Tue, Feb 17, 2009 at 5:58 AM, sara sabri <sar...@ya...> wrote: > Dear Frinds > Please someone help me > I would like to know if we could do MultiGaussian Kriging (MGK) with sgems. > If so how we could backtransform the results? I tried to do it by Trans > optin and assuming the hard data are Gaussian with a variance of 1. But the > variance generated are very close to each other,i.e. the variance of > variances is very small (e.g. conditional variances are between 18 to 19) > while for the ordinary kriging the variance is between 0.01 to 10 for > example. I really mixup. Please someone help me. > I really appreiate your patience and am looking forward to hearing soon. > Thanks in advance > Sara > > ------------------------------ > New Email addresses available on Yahoo! > <http://sg.rd.yahoo.com/aa/mail/domainchoice/mail/signature/*http://mail.promotions.yahoo.com/newdomains/aa/> > Get the Email name you've always wanted on the new @ymail and @rocketmail. > Hurry before someone else does! > > > ------------------------------------------------------------------------------ > Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, > CA > -OSBC tackles the biggest issue in open source: Open Sourcing the > Enterprise > -Strategies to boost innovation and cut costs with open source > participation > -Receive a $600 discount off the registration fee with the source code: > SFAD > http://p.sf.net/sfu/XcvMzF8H > _______________________________________________ > Sgems-users mailing list > Sge...@li... > https://lists.sourceforge.net/lists/listinfo/sgems-users > > -- Pierre Goovaerts Chief Scientist at BioMedware Inc. 516 North State Street Ann Arbor, MI 48104 Voice: (734) 913-1098 (ext. 8) Fax: (734) 913-2201 Courtesy Associate Professor, University of Florida Geostatistician, Computer Sciences Corporation President, PGeostat LLC 710 Ridgemont Lane Ann Arbor, MI 48103 Voice: (734) 668-9900 Fax: (734) 668-7788 http://goovaerts.pierre.googlepages.com/ -------------- next part -------------- An HTML attachment was scrubbed... ------------------------------ Message: 3 Date: Tue, 17 Feb 2009 10:51:27 -0500 From: Ben Scandella <bscand@MIT.EDU> Subject: [Sgems-users] Periodic sgsim To: sge...@li... Message-ID: <499...@mi...> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Greetings, Can sgsim be run to create a field that is periodic in one (or two) directions? How much modification would it take to implement? Thanks, Ben Scandella ------------------------------ ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H ------------------------------ _______________________________________________ Sgems-users mailing list Sge...@li... https://lists.sourceforge.net/lists/listinfo/sgems-users End of Sgems-users Digest, Vol 29, Issue 5 ****************************************** ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H_______________________________________________ Sgems-users mailing list Sge...@li... https://lists.sourceforge.net/lists/listinfo/sgems-users |