countour Smoothing surface elevation

[Anonymous]

Hello all. I have one request about surface spot elevation. when i put spot elevetions on minor contours they have same elevation 22.12 , but when i make contour smoothing they are changing. for example 22.12, 22.13, 22.08, ,   So,, what is reason can you help me?  thanks advance..

[ksorsby]

You are, by increasing the number of points in the surface, changing the interpolation of the levels at your spot elevation locations and therefore potentially changing the levels.

Neither are wrong, it's just interpretation of how the levels should be calculated.

Kevin

[AllenJessup]

Are you using Contour Smoothing or Surface Smoothing?

Here's a quote from my old boss that helps with dealing with these discrepancies:

"All Contours are lies".

Allen

[Anonymous]

I need smoothed contours and same elevations to write on surface .  But  it is impossible. yes? 

[ksorsby]

You could add your elevation labels, explode them then smooth the surface. Or use Cogo points instead of labels then smooth the surface.

Whichever, either the contours or labels will be wrong, hence Allens point above!

Kevin

[Anonymous]

[jmayo-EE]

Contour smoothing will not work. This routine will curve contours not the surface. This is why the elev's vary. As mentioed above smooth the surface but limit the area if the surface is large.

[AllenJessup]

If you MUST have spot elevation labels directly on the contour lines. You'll have to use Surface Smoothing which does alter the Surface by inserting interpolated points. The Surface wont be any better or worse but the contours will look smoother. This will also increase the size of your Surface.

Allen

[tcorey]

As others have already said, the way to make the contours match your data most closely is to use unsmoothed contours.

Is there a reason you don't use contour labels on the contours? These will show the same value that the smoothed contour represents.

If you must use Spot Elevations, even if you smooth the surface, don't smooth the contours or you'll have the same issue, maybe less so, but it won't go away completely.

If you care to entertain another workaround: Smooth the contours, extract the smoothed contours, make a surface from the extracted contours. It won't match the previous surface exactly, but the spot elevations will match the contours.

[AllenJessup]

You could create a Surface from contours as Tim outlined. Then use that Surface only for the labels. Keep the original Surface for everything else.

Allen