Question

Use 3D polygon as input for subsurface 3D elevation model

  • 6 July 2017
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Hi there,

I have a series of 3D points which are used for the creation of a subsurface strata elevation model.

Geological structures (faults) are generally only available as 3D lines, and can be used as breaklines for creation of the 3D surface in conjunction with known 3D points successfully.

Occasionally, a 3D polygon surface is given as a 3D representation of the fault plane, where if the fault plane is near vertical, the 3D polygon almost appears as two parallel lines in X,Y but closed at either end. While the X,Y distance between the polygon edges may be only <1m , the difference in Z may be tens of metres.

There appear to be many different approaches to incorporate this data into the creation of the elevation model, which include

1) Breaking the 3D polygon into 3D points , using chopper then using those point in the surface creation,

2) Breaking the 3D polygon into 2 x 3D lines using chopper then using those lines as breaklines in the surface creation with the other 3D known points.

3) Forcing the 3D polygon to a single 2.5D line with fixed Z value , then using that line as breakline. This approach does not accurately define the fault plane if the plane is say at 45 Degrees.

Any suggestions for other approaches or better ways of doing (1) or (2) above with FME transformers would be appreciated.

Thanks


1 reply

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The method to use will depend on the output you want.

If you want to create a 3d surface of any kind, I would recommend using the SurfaceModeller transformer. You can choose the output you need and adjust it or write it from there on.

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