Jagged contours & profiles

[mrsusan]

Hi,

I have received extremely large txt files (XYZ) to be used to make a surface in C3D. Bringing them in isn't a problem, but the contours display very jagged.

Ideally, I'd like both a smooth, accurate surface with a smooth profile, but it's mainly the profile I'm interested in (although seeming as it reads the surface, I'll have to mess around with that first).

I have tried sampling every, say 10 points which smooths it to an extent but I find that there are frequent large spikes in the profile, as well as it still being quite jagged. Using surface simplification and smoothing only seems to yield very minimal results. Sampling 20+ gives me even bigger data spikes.

I am using 2010, I understand that there is a profile line of best fit feature in 2011, but does anyone know if there is a way to smooth out the surface properly without data spikes or lots of data loss? Or do I tell the surveyor his data is bad?

Attached a picture as it would probably explain my predicament better than I can!

Thanks in advance

[jpaulsen]

First thing I would look at is adding breakline data to the surface. You should define breaklines everywhere there is a sharp change in grade. For example: top of slope, toe of slope, thalweg of ditch, flowline of gutter, top of curb, etc.

What does this surface represent? I have not seen many surfaces with negative elevations.

[mrsusan]

Thanks for the reply. I'm just stepping out of the office, but I'll try the breaklines tomorrow. The surface is of a sea bed :)

Thanks

[tntdraftsol]

A question I would have is how did they obtain the surface data? In my expierence sometimes data that is taken using a Lidar method could give those spikes if it bounced off something that was not true ground. Just a thought.

[dgordon.68443]

mrsusan,

did you ever get your situation resolved?

Dan

[mjfarrell]

This would suggest that a higher level of detail is required given the size of the surface area.
In short, MORE points would assist in creating a more well defined surface.
My guess is you have nothing to use to discreetly add breaklines to the file.
Another alternate woud be to edit the surface and Swap Edges to normalize the contours somewhat.
This will be a best guess as you say it is a seabed, and no one has actually laid eyes on the surface these points describe.

You can use the Surface>>Edit Surface command
and attempt to Smooth or Simplify the surface.

The data isn't exactly 'bad' it's that you probably need a higher order of points to better describe what's happening under there.

Th best fit profile is more or less for design purposes.

[mrsusan]

Hi there,

Sorry for the delay in reply, I forgot my log in details. In the end I had to submit the profiles and data as they were due to the client not wanting any degree of smoothing (odd I know!), it is an extremely rough seabed although the data still looks a little too jagged for my liking. It is 1x1m data.

I have just installed C3D 2012 so will have a play and see if there's anything nice there. Any suggestions are always welcome, I shall try swapping the edges.

FYI, here is an elevational band I made for a little section of the seabed. As you can see, it's not the most pleasant of places to route a pipeline!