Norway water: N50 Arealdekke vs NVE ELVIS — pick the Strahler source deliberately #228

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opened 2026-08-24 17:08:01 +00:00 by art-bot · 0 comments

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2026-08-24 17:08:01 +00:00

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Gated on #210, #217 and #219. Covers water_bodies, waterways and water_points.

Two competing sources, and the choice is the substance of this issue:

N50 Arealdekke (Kartverket, CC BY 4.0) — confirmed from delivered GML:
Innsjø (1 105 in Alvdal alone) with vatnLøpenummer, Elv (rivers as areas),
ElvBekk (narrow watercourses as lines, with vannbredde), and crucially
ElvMidtlinje and InnsjøMidtlinje — the throughflow centrelines through river
areas and lakes. Those centrelines are exactly the piece Greece's WFD data lacked, so a
connected network is reconstructible.
NVE ELVIS elvenett (3f95a194-0968-4457-a500-912958de3d39, NLOD) — a
purpose-built connected river network, plus NVE Innsjødatabase
(823b8639-…, NLOD) for lakes with numbers, names and areas.

N50 lake polygons are unnamed inline — vatnLøpenummer is the join key to the NVE
lake database, or names can come from StedsnavnTekst. Decide which and say why.

Recommendation to test rather than assume: ELVIS for waterways (it is built to be a
network), N50 Innsjø + NVE names for water_bodies. Measure both for connectivity
before committing — "purpose-built" is a claim on a product page until a Strahler run
proves it.

water_points: do not declare either way yet. N50's full object catalogue has not
been enumerated — the class lists above come from two delivered municipalities — and NVE
publishes waterfall registers. R6 requires the provider's complete published class list
before an absence is written down. Norway has waterfalls; the question is only whether they
are a surveyed class.

Gated on #210, #217 and #219. Covers `water_bodies`, `waterways` and `water_points`. Two competing sources, and the choice is the substance of this issue: - **N50 `Arealdekke`** (Kartverket, **CC BY 4.0**) — confirmed from delivered GML: `Innsjø` (1 105 in Alvdal alone) with **`vatnLøpenummer`**, `Elv` (rivers as areas), `ElvBekk` (narrow watercourses as lines, with `vannbredde`), and crucially **`ElvMidtlinje` and `InnsjøMidtlinje`** — the throughflow centrelines through river areas and lakes. Those centrelines are exactly the piece Greece's WFD data lacked, so a connected network is reconstructible. - **NVE ELVIS elvenett** (`3f95a194-0968-4457-a500-912958de3d39`, **NLOD**) — a purpose-built connected river network, plus **NVE Innsjødatabase** (`823b8639-…`, NLOD) for lakes with numbers, names and areas. **N50 lake polygons are unnamed inline** — `vatnLøpenummer` is the join key to the NVE lake database, or names can come from `StedsnavnTekst`. Decide which and say why. Recommendation to test rather than assume: ELVIS for `waterways` (it is built to be a network), N50 `Innsjø` + NVE names for `water_bodies`. Measure both for connectivity before committing — "purpose-built" is a claim on a product page until a Strahler run proves it. **`water_points`: do not declare either way yet.** N50's full object catalogue has not been enumerated — the class lists above come from two delivered municipalities — and NVE publishes waterfall registers. R6 requires the provider's complete published class list before an absence is written down. Norway has waterfalls; the question is only whether they are a surveyed class.

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2026-08-24 17:08:01 +00:00

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2026-08-24 17:18:38 +00:00

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