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

[MORREALE Jean Roc]

Thanks for the answers,

Having used it a little with archaeological structures it was no wonder 
that the first software I thought about was grass, but the main 
difference is, as you pointed out, that in this case I do not have a 
well defined volume.

I was thinking about using r3.in.ascii and then r.to.rast3 but it 
doesn't seems to be the right thing to do on a large scale (150km²) due 
to potential multiple top/bottom crossing of the generated layers.

Your screenshots are exactly the kind of data visualization I'm seeking 
to obtain.

Jean Roc

Le 08/01/2010 00:34, Benjamin Ducke a écrit :
> Well, you are in luck and trouble at the same time. Out of all GIS I
> know, GRASS is the only one that's competent at handling 3D,
> volumetric rasters (aka voxels, which is really what you want for
> stratigraphic models). On the other hand, efficient voxel modelling
> from sparse 3D data, such as well logs and transects remains really
> challenging.
 >
 > The problem with well logs is also that often the data is of a
 > "qualitative" nature, indicating the presence and absence of types of
 > material. There is no interpolation algorithm in GRASS currently
 > which can handle that sort of data well.
 >
> I have attached two screenshots of models that I once produced from
> log data. One has been interpolated with GRASS' 3D splines algorithm
> (which was a bit cheating, really), the other is some sort of 3D IDW
> interpolation done directly in VisIt. I don't think they turned out
> too great.
 >
> But, hey: it's still more realistic than drawing on a piece of paper
> and playing the old "connect the logs with lines" game...

You missed the use of Illustrator

> Ben
>
>
> MORREALE Jean Roc wrote:
>> Hello Grasslist,
>>
>> I'm searching for papers, books or usecases covering the use of
>> GRASS in geology, mainly on the stratigraphic representations (well
>> log, schematic block diagram) and geomorphological (erosion,
>> georelief reconstruction) aspects.
>>
>> This is an area I've not practiced so far so I would be interested
>> to know how people here deal with it  in Grass (especially their
>> rules for building a 3d model from logs and exploiting it correctly
>> but also any kind of spicy stuff you can obtain from it).
>>
>> Thre is some related papers I've already find on these subjects :
>>
>> HydroGIS 96: Application of Geographic Information Systems in
>> Hydrology and Water Resources Management (Proceedings of the Vienna
>> Conference, April 1996). IAHS Publ. no. 235, 1996.
>>
>> Spatial Geologic Hazard Analysis in Practice, J. David Rogers,
>> 2004
>>
>> Three-dimensional Geological Modeling by FOSS GRASS GIS, Atsushi
>> Kajiyama et al., 2004
>>
>> Volume modeling of soils using GRASS GIS 3D-Tools, Markus Neteler,
>> 2001
>>
>> Regards, MORREALE Jean Roc
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>>
>
>
>
>
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