Stream extraction mistaking roads as streams

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08-29-2019 06:21 AM
SarahWells
New Contributor

I am finding the watershed and streams in an area that contains a few roads. It is mistaking some of the roads as streams. How do I make sure the stream extraction isn't picking up the roads as well?

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4 Replies
ThomasColson
MVP Frequent Contributor

When you say picking up roads as streams, I'm assuming your source DEM is detailed enough to treat the road bead as a shallow stream channel (curb and gutter). This is pretty common in hydro network extraction. What you need to do is "burn" each road crossing over a stream such that the elevation drop across the road carries your flow direction downstream, and not making a hard turn onto your road. 

SarahWells
New Contributor

Thank you! I will try this.

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SarahWells
New Contributor

A lot of what I am finding online is burning stream networks into DEM. Is this process going to be different with roads? Some of the sources online aren't very clear.

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ThomasColson
MVP Frequent Contributor

At the risk of being egotistical, I explored a lot of different ways to "condition" dems for stream network extraction. Been a few years, but I think you want a tool called "Whitebox GAT". 

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