I am trying to find the shortest downstream path from point to point on a stream network using QNEAT3 1.0.4. The network shapefile has a direction of flow field and the following attributes:
20|Not Identified|Unknown, not listed, not applicable or impossible to determine.
32|Same Direction|The flow direction and the digitizing direction are the same.
33|Opposite Direction|The flow or event direction and the digitizing direction are opposite.
34|Not Applicable|Not Applicable
I am using this plugin in the QGIS graphical modeler and for the most part the results are ok; however, some of the results don't make any sense, and both the network and points are projected to a projection suitable for the area.
For example, the OD matrix has many of the same distance results for different pairs but one distance, a total cost of 5.3712608 m, is not associated with any point pair. However, there is another origin-destination point pair that does have a distance of 5.3712608 m, which is correct. Is it possible that some of the previous calculations are 'leaking' into this origin-destination iteration result?
The correct pairing is Origin = 4 and Destination = 21 (circled in yellow & screen shot). It would be fine if the two distances of 12902 m and 14751 m are in the table because I can screen out the other downstream distance of 14751 m and just take the lowest, but the nonsensical value of 5.3712608 m in the table makes it so I can't do this.