Contour lines jagged, not smooth

When loading contours from a TIN using "Load DTM Features" in GeoPak, the contour lines are not smooth and straight. The contoured area can be a steady/constant slope with constant elevation at top of slopw and constant elevation at toe of slope and the contours will not be smooth and/or straight. Is there a way to improve the "stroking" (?) of the lines/curves to create a "smoother" contour line?

I'm using breaks and spots when creating the DAT file and I have experimented with the "stroking" settings (Curve Tolerance & Min Linear Distance) with minimal success. Perhaps I'm expecting too much but I've seen other files with perfect line segments and arcs for contours (don't know the creator of the files).

Is there another method of generating/loading contours with GeoPak?

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Offline MichaelGilham Wed, Sep 2 2009 9:19 PM
Hi,

did you try drawing the contours with B-Spline smoothing enabled?

Its a smoothing option on the Load Features>Contours dialog.

It may help...
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David Conner Fri, Sep 4 2009 4:48 PM in reply to MichaelGilham

I think I just may have my expectations too high. I have tried ALL of the options available. My goal is to have the contours follow along as the break lines do. My break lines are all "clean" line segments and arcs. When the contours are created by GeoPak they are "jagged" b-splines. I don't mind that they are b-splines but they don't run straight nor are the curves smooth.
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Offline Dan Calistrat Fri, Sep 4 2009 5:03 PM in reply to David Conner

It sounds as if the breaklines weren't picked up at all. Maybe post a before and after pic? Also in the DTM Toolbar, select Reports>Triangle Statistics which gives you a breakout of the exact # and type of features created in the TIN file. Make sure the report matches the existing graphics; uou can use MicroStation's powerselector to easily isolate the various feature types.
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Offline MichaelGilham Fri, Sep 4 2009 5:41 PM in reply to Dan Calistrat
Hi David,

can you post some sample data - so we can take a look?

Thanks,
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Offline neilw Fri, Sep 4 2009 11:29 PM in reply to MichaelGilham
Typically the jagged contour behavior occurs when there is a breakline with only a few points that is triangulating to another breakline with lots of points. A classic example is at a curb return on a roadway where the crown of the roadway has a large stroking interval while the curb return has high density interval. Try inspecting your data for this situation where you see the jagged contours and densify the data by some means to correct it.

Neil Wilson (aka Neilw)

Power Civil v8i 08.11.07.245

AutoCAD Civil 3D 2018
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Offline neilw Fri, Sep 4 2009 11:29 PM in reply to MichaelGilham
Typically the jagged contour behavior occurs when there is a breakline with only a few points that is triangulating to another breakline with lots of points. A classic example is at a curb return on a roadway where the crown of the roadway has a large stroking interval while the curb return has high density interval. Try inspecting your data for this situation where you see the jagged contours and densify the data by some means to correct it.

Neil Wilson (aka Neilw)

Power Civil v8i 08.11.07.245

AutoCAD Civil 3D 2018
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Offline Rousenator Fri, Aug 2 2013 4:40 AM in reply to neilw

Hi everyone,

i use Geopak for my DTM construction and have found that the best way of achieving a 'smooth' DTM is by creating a LATTICE as opposed to a TIN. Its the best way of removing 'sharps' that are created by the contour data used, without having to smooth out the contour linestrings.
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