•Check Shreve and click OK. Progress can be followed in the status bar. Large networks will have large topological dictionaries and will take longer to process.
•Shreve stream ordering orders the network by starting at the source and travels down the network incrementing the order of the polyline. It repeats this process for every source.
•The output of a Shreve stream order is a single field in the attribute table of your river network called Shreve with the stream order of the polyline. If the Shreve field already exists then a new field is created with an index number at the end, e.g. Shreve2.
•Shreve stream order is not designed for multi-channelled networks. If RivEX encounters a section of multi-channel network such as a braid it will choose a SINGLE route through this section. All other polylines within the multi-channel section remain encoded as ZERO. This route is based purely upon the row order of polylines in the table, i.e. the order in which it was digitised. This order is not always the main course of the river so caution should be used when interpreting the output for river networks with loops.
A network colour coded by Shreve Stream order,
this river achieves a 7th order
•Shreve ordering will terminate before processing ends if whilst attempting to order your network it discovers a polyline that points in a mouth to source direction. The algorithm terminates and logs the To-Node ID number. It then starts to order from another source. The erroneous node ID's are written to the Error Log file ..\RivEX_Workspace\ErrorLogs\ShreveNodeFailures.txt.
• To deal with any errors you must:
1.Step through the Error Log file file and correct all polylines, you do this by
2.Search for the polyline with a ToNode ID as reported
3.Flip the appropriate polyline
4.Once all entries in the Error Log file have been processed rebuild from- and to- node fields
5.Re-run the Shreve stream ordering tool