GNAT

Calculate Threadedness

The Calculate Threadedness tool calculates the degree of threadedness for a stream network. In this case, “threadedness” is defined as the number of braids that intersect mainstem reaches within the stream network. The tool plots intersection nodes, determines the node type, and then calculates the number of nodes for each stream reach feature. Three node types are plotted, including:

  • braid-to-braid
  • braid-to-mainstem
  • tributary confluences

threadedness_example

Usage

Geoprocessing Environment

  • We recommend running the tool using 64-bit python geoprocessing.
  • Disable Z and M values in the input stream network feature class Shape field.

Input Parameters

Input segmented stream network (with Stream Order)

A stream network feature class previously segmented by theSegmentation tool, from which all braid features have been manually removed. New fields will appended to this dataset on completion of the processing.

Input stream network with braids

Stream network feature class which includes multi-threaded streams ((i.e. braid features).

Scratch workspace

  • Can be a file geodatabase or folder, which will be used for saving temporary processing datasets.

Output

Output network nodes

Point feature class representing three node types:

  • braid-to-braid nodes
  • braid-to-mainstem nodes
  • tributary confluences

Please note: If this analysis is part of Riverscapes project, the Input Stream Network will automatically be switched to the stream network feature class associated with the Realization Analysis found in the project.rs.xml file, which the user selects in the Riverscape Project Management parameters of this tool.

Riverscapes Project Management

Is this a Riverscapes Project? (optional)

  • Check box indicating whether this analysis is part of an existing Riverscapes project.

GNAT Project XML (optional)

  • XML file (should be named project.rs.xml) which stores information on the associated Riverscapes project.

Realization Name (optional)

  • Name of the project Realization selected from a list of existing Realizations. Only one Realization can be selected.

Segmentation Name (optional)

  • Name of the Segmentation Analysis selected from a list of existing Analyses, to which the Calculate Threadedness analysis will be assigned.

Attribute Analysis Name (optional)

  • Name of the new Calculate Threadedness analysis.

Technical Background

Calculation Method

Manual Preprocessing

  1. Process stream segmentation (1000m and/or 500m).
  2. Find braids in a separate stream network feature class (after topology clean-up, removal of canals, etc.).

Automated Processing

  1. Select braids segments using IsBraided attribute field
  2. Remove from selection the currently selected braid features that share a centroid with stream features in segmented stream network.
  3. Dissolve selected braids (using “single part” parameter)
  4. Self-intersect dissolved braids to get “braid-to-braid” nodes.
  5. Intersect selected braids with segmented stream network - produces “braid-to-mainstem” nodes (which results in “Multipoints”).
  6. Convert braid nodes from multipart to single part
  7. Add new attribute field (“node_type” = ‘braid’)
  8. Dissolve segmented stream network (single-part)
  9. Self-intersect dissolved stream network to get “tributary confluence” nodes
  10. Add new attribute field (“node_type” = ‘confluence’)
  11. Merge node datasets into new feature class
  12. Spatial one-to-many join between stream segment features and braid node features.
  13. Summarize by LineOID
  14. Calculate count of braid nodes per stream segment
  15. Spatial one-to-many spatial join between stream segment features and confluence node features
  16. Summarize by LineOID 19j. Calculate count of tributary confluence nodes per stream segment