Catchment hierarchy (Task 2.2)

[JamesSample]

NVE have previously told me that the regine dataset does not include any explicit up/downstream information, other than what is encoded in the alphanumeric naming convention. Dealing with all the edge-cases in the regine codes will be tricky, but the first thing to check is what the vnrOFelt field in the regine attribute table actually signifies. According to NVE's documentation it's the

Vassdragsnummer for overordnet nedbørfelt.

which might actually be what I'm looking for (?).

Needs further investigation...