I-data model (filter constrain - polygon)

[Daniele]

Hy,

I'm modelling I-data (chemestry data) based on boreholes samples.

Boreholes are located designing a "P".

I need to filter I-data with Filter Constrain Polygon and assign 1 polygon for entire area. I need also to assign a second polygon to avoid model inside interior sub-area.

How can I deal with?

Thanks

DLattuada

Attached borehole map and polygon 1 and 2 map.

[Molly]

Hi Daniele,

If your goal is to filter an existing I-Data model (the MOD file) with the two polygons, you will need to do this in two steps.

1) Use the Solid / Filter / Polygon Clip option to filter 1.MOD -> 2.MOD using one of the polygons.

2) Use the Solid / Filter / Polygon Clip option to filter 2.MOD -> 3.MOD using the other polygon.

(Or, you can apply one clipping polygon as you are creating the I-Data model; then run that model through the Polygon Clip with the second polygon.)

If you need help defining the vertices of the clipping polygons, you can use the Digitize / Polygon option in RockPlot2D (using, for example, a borehole location map) and save the numeric data only in a text file which can become your clipping polygon table. Only one polygon can be defined per table.

I hope I understood your question correctly - let me know if you need more information.

Molly Mayfield

RockWare Inc

molly@rockware.com

[Daniele]

Thanks,

Ok for clipping an exixting I-data model and using the digitizer.

But what concerning the creation of a new model? I would like Rockworks not interpoling data throught inside polygon used for filtered datas.

If i clip the model I will have it cut off but what I'm looking for is not to have the model been created inside the polygon.

Any suggestions?

Thanks.

DLattuada

[Molly]

Hi Daniele - I don't think I completely understand your question, sorry!

RockWorks MOD files must be a regular, continuous, 3D array of nodes, each assigned a G value. It is not possible to not-create the model inside the polygon. You CAN assign those nodes a null value so that they are 'invisible' from view, from volume computations, etc. You can assign the nodes the null value as you are interpolating the model or after the model has been created. Since you have 2 polygons, the null filter must be run in 2 passes.

If this still does not answer your question, you can feel free to direct further inquiry to me by email (molly@rockware.com) or in Italian to our Swiss office: europe@rockware.com

Molly Mayfield

RockWare Inc

[Daniele]

Sorry for this late follow up, but I was not in the office.

If you have confidence with Surfer, what I was looking for is called a "fault". A fault is a two dimensional blanking file acting as a barrier to information flow when gridding. Data on one side of the fault is not directly used when calculating grid notes value on the other side of the fault.

Is it possible to create a model in such a way?

Thanks.

DLattuada

[Molly]

No, RockWorks doesn't offer faulting for solid modeling, only for 2D gridding (with inverse distance or mlr).

You can turn off boreholes so that their data is not used in the modeling process, but you cannot define a blanking area.

Molly Mayfield

RockWare Inc