Smooth Polyline without Crossing Polygon Container

07-22-2011 09:18 AM
New Contributor III
I have hydrographic flowlines which I would like smoothed. For each flowline there is a polygon surrounding it (the river's floodplain). Even if I reduce the tolerance down to a small number in some areas the flowline is crossing the floodplain boundary, which cannot happen in our model. I would like to retain a smoothing of between 500-1000m.

Is there a method that can tell the smoothed lines not to cross a certain polygon boundary? Would incorporating the underlying NED help in any way. I have been racking my brain for 2 weeks on this issue and have yet to find a resolution.

I attached a Word doc to show you the issue.

Thanks you, James
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1 Reply
by Esri Regular Contributor
Esri Regular Contributor
Perhaps you can try to Buffer the flow lines first with 500m and see where the buffer lines cross the flood plain polygons. You might need to use Feature To Line tool to convert the buffer polygons into lines and then use Intersect tool to analyze the crossings.

Once you know where the buffer crossing is, you can try to use those buffer polygons to select the flow lines. For these selected flow lines, try a smaller smoothing tolerance?

Having said the above, I actually wonder if you could smooth the flood plain polygons. Since you are allowing a significant change/reduction of accuracy for the flow lines, it may make sense to allow similar smoothing of the flood plain boundary to match the change in flow lines. That particular 90 degree corner (seemingly converted from a raster edge) could be smoothed away from the smoothed flow line.

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