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I will try my best to describe my question here: All the operations are done with ArcMap 10.1. I have a shapefile, which represent the stream segment network of a watershed produced from ArcHydro tool.

I need to break each stream segment into reaches with a fishnet using intersect tool. After the intersect operation, one single stream segment is represented by several reaches. However, the original stream segment has attributes named "from Node" and "to Node". After intersection, all reaches are seemly the same in attributes and I can't tell the sequence of them at all.

So how should I rebuild the direction information for these stream reaches?

  • Do you have an Advanced license? What if you use Identify instead of Intersect? No idea if this will work, just a thought. If not, I can only think of ways to get the same from/to attribute applied to the new segments, but that means more than one segment would have the same from/to attributes (so groups would order but within a group they wouldn't). Rebuilding the directions might be the way to go depending on your use. – Chris W Dec 4 '14 at 22:16
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Guess I am gona answer my own question here.

So basically I spent a little walk with the C# ArcObject coding.

Steps are abstracted for understanding: 1. Open the stream shapefile, store the object id information; 2. Open the intersect shapefile, search for the record for each original object id, such as there are 68 reaches for stream id 1; 3. Use two list to store the frompoint and topoint for each reach using ISelectionSet; 4. For loop to find the start point, which is one never showed up in the topoint list; 5. Write out sequence into a new field or any text depending on your need.

Not the smartest way, but it works!

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