I have a large stream layer that is split into a series of segments. The segments do not have any stream ID or similar that I can dissolve by to consolidate back to streams. Can anyone point me in the right direction for a tool or method I could use to achieve this? I am using ArcGIS 10.0.

The screenshot below illustrates the stream layer and how it is split into segments. I have found other solutions elsewhere on the site like here:How to Unsplit/Dissolve multiple touching lines in Stream Network?

but it doesn't seem to work in this instance...

enter image description here

If I use the dissolve function, it dissolves all of the segments back to 3 FIDs. Similarly, unsplit tool does not work on this layer - segments remain separate.

  • 1
    If the start node of one segment coincides with the end node of the previous segment, you should use Dissolve. If not, please add a bit more detail do your question, and preferably a screenshot. – Martin Aug 24 '15 at 5:55
  • Hi Martin, the dissolve function distills all of the segments back to 3 FIDs for some reason. – Sicyopterus Aug 24 '15 at 6:28
  • In which way is that different from how you'd like it? Do you want each stream as one feature? Did you have the "Create multipart features" checkbox checked? Try using the "Unsplit lines" box instead. To split features that are non-connected but still the same row in your shapefile, you should use the Multipart To Singlepart function. – Martin Aug 24 '15 at 7:04
  • I want each stream to have its own ID and for all segments in each stream network to be merged together. The unsplit tool did not work for this layer and did not result in any consolidation of stream segments. – Sicyopterus Aug 24 '15 at 7:15
  • The Multipart To Singlepart function did not work either - all segments remain split. – Sicyopterus Aug 24 '15 at 7:21

Edit: Here is a first version of the tool:


Notes: - Only specify shapefiles as input and output. - The tool should not damage your input but still better back it up. - The tool uses tools that require Advanced ArcGIS or ArcInfo license.

If it works for you and no easier solution will come up I'll improve the tool.

Unsplit lines won't work for channels that branch off. Good news: I've written a draft of an algorithm that handles this specific issue, since it has risen more than once. Bad news: It's too crude to publish, requires my hands on involvement. I will work on it and publish as a tool here soon. If it's a layer you can share, James, perhaps I can help right now.

Here is a picture that demonstrates the tool:

Before on the left, after on the right

  • This looks good and thanks for the input. I don't know how to use the tool you have linked to above though. The layer can be shared no worries. I'm amazed that there isn't an existing tool that serves this function already. – Sicyopterus Aug 24 '15 at 23:48
  • Simply input and output Shapefiles to specify. The input is your layer, the output is the outcome unsplit layer. To use the tool locate it in the Catalog window (where you browse through files) and double click it. If you can link to the layer, please do. – Nir Aug 25 '15 at 4:42
  • For some reason it is not opening when I double click on it. Thanks for your patience with this...What is the best way to link to a layer? – Sicyopterus Aug 25 '15 at 4:51
  • You may send it to me fulmannir@gmail.com if it's not too large. Perhaps it doesn't work for you because of licenseing issues. – Nir Aug 25 '15 at 4:58
  • 1
    Nir, thank you so much for your help - you went above and beyond! Absolute legend and GIS wizard. – Sicyopterus Aug 26 '15 at 23:19

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