[GRASS-user] Searching Docs about 3D geological modelisation

[Dylan Beaudette]

Hi Thomas,

I am pretty sure that the program (maybe not the source code) are in
the public domain.

I'll contact the author, and post back.

Cheers,
Dylan

On Mon, Jan 11, 2010 at 6:56 AM, Thomas Adams <Thomas.Adams at noaa.gov> 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.ducke at 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.html#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 at 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.ducke at oadigital.net
>>>>> http://oadigital.net
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
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>>>>
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>>>>
>>>>
>>>>
>>>
>>> --
>>> 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.ducke at oadigital.net
>>> http://oadigital.net
>>>
>>>
>>>
>>>
>>>
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>>>
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>>>
>>
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>
>
> --
> Thomas E Adams
> National Weather Service
> Ohio River Forecast Center
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