Replace region of surface with another surface

[cattjake]

Good Morning,

I will try to explain this in a few steps to outline my situation and my desired outcome.

The two surfaces I am working with are: an EG ground surface from survey data that is very detailed and secondly a groundwater elevation surface (GW) which is very idealized from just a few monitoring locations which were used to create the surface.

My desire is everywhere the GW surface is above the EG surface to have that region on the GW surface equal EG exactly. I can delineate the areas by creating a volume surface and seeing where 0 elevation is. But what is the best way to replace those GW regions inside of the 0 area with EG?

In the past I have accomplished this task by doing a save as of the EG and adding one of the regions as a boundary, renaming to EG Region 1 then pasting this region onto the GW surface. The problem with this method is a new EG Region surface has to be created for each area you wish to have equal and my current comparison has LOTS of little areas where the GW is above the EG.

Is there a better method?

Is there any method that is dynamic?

[ericcollins6932]

Hmmm - try the autobalance tool to give you the best shift of one surface to another to achieve balanced cut and fill. This tool will provide how much you will need to shift one surface to balance with the other - a best fit if you will.

[neilyj666]

Not sure this would be valid for a groundwater surface as cut and fill is not the issue.

By definition a spring would occur where the groundwater surface meet the EG, is this what is happening?

I would tend to model the groundwater based on depths from EG and using similar techniques as I do for subsurface strata horizons.

[cattjake]

Yes, by definition if GW was above EG the water would be expressing its self. But that is beside the point.

I am highly simplify both my current drawing, surface names and other details as to not clutter the issue at hand:

What is the best procedure to 'paste' EG TIN data into the GW surface within the regions EG is above the GW surface?

Or if this helps

What is the best procedure to 'paste' Surface 1 TIN data into Surface 2 within the region where Surface 1 has greater elevation than Surface 2?

Thank you for your continued help.

[ericcollins6932]

I would clip the EG surface using the volume surface to provide the 0 elevation contours where EG is above GW as the clip boundaries. Then paste that clipped surface into your GW surface. A little bit of manual work depending on how many regions you have where this occurs and how big your AOI is.

[cattjake]

There are about 30 regions

[ericcollins6932]

Better than 300!

[neilyj666]

Not sure why you are needing to do this or the validity of your groundwater surface but that is another topic..........

1. Use the MINIMUMDISTBETWEENSURFACES function to get the "springline" i.e. the interface contour but you may also need to manually edit to get closed boundaries.
2. Create a new surface and paste the GW surface into it and extract the surface boundary.
3. Use the GW surface boundary as a HIDE boundary and then add the zero contour boudaries as SHOW boundaries
4. Paste this surface into the OGL surface (may want to create a copy of the OGL surface first and then paste into the copy rather than the original)

[jmayo-EE]

Does this help? Perhaps you need a transition area to smooth out some data.

http://www.civil4d.com/2010/04/blending-surfaces/