Hey, good news. Please keep us updated! Ben
----- Original Message ----- From: "Dylan Beaudette" <debeaude...@ucdavis.edu> To: "Thomas Adams" <thomas.ad...@noaa.gov> Cc: "grass list" <grass-user@lists.osgeo.org> Sent: Wednesday, January 20, 2010 8:10:45 PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna Subject: Re: [GRASS-user] Searching Docs about 3D geological modelisation Quick update: I recently heard back from Graham Fogg here on campus, and he is in favor of allowing T-PROGS to be used within GRASS. However, he is still waiting for the final go-ahead from the original author. Dylan On Monday 11 January 2010, Thomas Adams wrote: > Dylan, > > Can you tell me how to obtain TPROGS? Is it only available commercially? > > Thanks, > Tom > > Dylan Beaudette wrote: > > Two more ideas: > > > > 1. conditional simulation, based on a 3D variogram model > > 2. transition probability-based interpolation of categories > > > > Check out gstat for the conditional simulation, and TPROGS for the > > transition probability. If anything is interested, I have done some > > programming to connect GRASS and TPROGS. > > > > Cheers! > > > > Dylan > > > > On Fri, Jan 8, 2010 at 1:24 PM, Benjamin Ducke > > > > <benjamin.du...@oxfordarch.co.uk> wrote: > >> Woohoo, this forum is always a treasure trove > >> of good advice. I had not idea SGemS existed! > >> The Voronoi idea is also good, I am just not sure > >> that the 3D Voronoi diagram is quite what one > >> would instinctively think it is. > >> > >> http://en.wikipedia.org/wiki/Voronoi_diagram > >> > >> says: "In general a cross section of a 3D Voronoi > >> tessellation is not a 2D Voronoi tessellation itself." > >> > >> Need to look into that. > >> > >> I don't have much practical experience > >> with Bayes models, so can't really comment on > >> that. > >> > >> Cheers, > >> > >> Ben > >> > >> Christian Kaiser wrote: > >>> It seems to me that this is a 3D interpolation problem with categorical > >>> variables. > >>> > >>> Maybe the Bayesian Maximum Entropy approach could help. There are some > >>> interesting publications around also for geology and soil sciences, and > >>> they can deal with categorical data as well. Look for example here: > >>> http://www.enge.ucl.ac.be/staff/curr/Bogaert/biblioBME/BMEbibsubject.ht > >>>ml#Soil%20Science > >>> > >>> Or maybe you can have a look at SGeMS (http://sgems.sourceforge.net), a > >>> tool for 3D geostatistics. > >>> > >>> None of them is available through GRASS, but the algorithms are freely > >>> available (I think open-source, but not verified). > >>> > >>> I am not a geologist, so please forgive if it is not adequate... > >>> > >>> Christian Kaiser > >>> > >>> On 8 janv. 2010, at 11:04, Benjamin Ducke wrote: > >>>> Rich Shepard wrote: > >>>>>> material. There is no interpolation algorithm in GRASS currently > >>>>>> which can > >>>>>> handle that sort of data well. > >>>>> > >>>>> So what is needed is a political algorithm. :-) > >>>> > >>>> That's actually right: given the presence of n different > >>>> layer types in the vicinity of an empty voxel, the algorithm > >>>> would need to decide by some sort of "majority vote" > >>>> which type to assign to that voxel. > >>>> > >>>>> Kidding aside, I suspect that a fuzzy interpolation algorithm would > >>>>> solve the problem. > >>>> > >>>> How? You could make the interpolated value depend on a > >>>> fuzzy set member function, I suppose, but the situation > >>>> here is actually so well defined that I think a probabilistic > >>>> approach would be preferable. Since each voxel can only > >>>> store one value, a second output map could store the > >>>> classification probability. That may be very useful > >>>> for visualization (you could show voxels with little > >>>> probability hazier). > >>>> > >>>> Ben > >>>> > >>>>> Rich > >>>>> _______________________________________________ > >>>>> grass-user mailing list > >>>>> grass-user@lists.osgeo.org > >>>>> http://lists.osgeo.org/mailman/listinfo/grass-user > >>>> > >>>> -- > >>>> Benjamin Ducke > >>>> Geospatial Consultant > >>>> > >>>> Oxford Archaeology Digital > >>>> Janus House > >>>> Osney Mead > >>>> OX2 0ES > >>>> Oxford, U.K. > >>>> > >>>> Tel: +44 (0)1865 263 800 (switchboard) > >>>> Tel: +44 (0)1865 980 758 (direct) > >>>> Fax :+44 (0)1865 793 496 > >>>> benjamin.du...@oadigital.net > >>>> http://oadigital.net > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> ------ > >>>> Files attached to this email may be in ISO 26300 format (OASIS Open > >>>> Document Format). If you have difficulty opening them, please visit > >>>> http://iso26300.info for more information. > >>>> > >>>> _______________________________________________ > >>>> grass-user mailing list > >>>> grass-user@lists.osgeo.org > >>>> http://lists.osgeo.org/mailman/listinfo/grass-user > >>> > >>> _______________________________________________ > >>> grass-user mailing list > >>> grass-user@lists.osgeo.org > >>> http://lists.osgeo.org/mailman/listinfo/grass-user > >> > >> -- > >> Benjamin Ducke > >> Geospatial Consultant > >> > >> Oxford Archaeology Digital > >> Janus House > >> Osney Mead > >> OX2 0ES > >> Oxford, U.K. > >> > >> Tel: +44 (0)1865 263 800 (switchboard) > >> Tel: +44 (0)1865 980 758 (direct) > >> Fax :+44 (0)1865 793 496 > >> benjamin.du...@oadigital.net > >> http://oadigital.net > >> > >> > >> > >> > >> > >> ------ > >> Files attached to this email may be in ISO 26300 format (OASIS Open > >> Document Format). If you have difficulty opening them, please visit > >> http://iso26300.info for more information. > >> > >> _______________________________________________ > >> grass-user mailing list > >> grass-user@lists.osgeo.org > >> http://lists.osgeo.org/mailman/listinfo/grass-user > > > > _______________________________________________ > > grass-user mailing list > > grass-user@lists.osgeo.org > > http://lists.osgeo.org/mailman/listinfo/grass-user -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user ------ Files attached to this email may be in ISO 26300 format (OASIS Open Document Format). If you have difficulty opening them, please visit http://iso26300.info for more information. _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user