Water deepening: names, ditches, reservoirs #21

New issue

Open

opened 2026-08-01 19:12:55 +00:00 by art-bot · 0 comments

art-bot commented

2026-08-01 19:12:55 +00:00

Collaborator

Names — only Poland labels its water. BDOT10k carries NAZWA on 87% of river polygons,
1.8% of lakes and every large canal, so the style's water_body_labels/waterway_labels
today label Poland alone. Iceland's names would come from the LMÍ örnefni dataset (which
is already fetched and unimported, and would also fix unnamed peaks and unnamed
waterfalls/springs); Sweden's from the Topo 10 text theme, which is in the Geotorget order
we already have. This is the highest-value of the three.

Ditches. Iceland's vatnafar has 93.6k (yfirbordsvatn = 2) and Poland's BDOT10k has
OT_SWRM_L; both are deliberately excluded today. If they are ever wanted, note that
Iceland's would have to be kept out of the Strahler graph — they are not part of the
natural drainage network and would distort the stream ordering.

Sweden's reservoirs. Topo 10 mark distinguishes 2634 "Anlagt vatten" and carries a
reglerat_vatten flag. Both collapse to lake today because the shared water vocabulary
has no reservoir and no other country can produce one — so this one is a vocabulary
decision first, not an import.

Three separate gaps in the water layers, all needing a dataset we do not currently fetch, so all were out of scope under Phase 3's stopping rule ("no new source datasets to reach a deeper class"). All are cheap-ish to revisit. **Names — only Poland labels its water.** BDOT10k carries `NAZWA` on 87% of river polygons, 1.8% of lakes and every large canal, so the style's `water_body_labels`/`waterway_labels` today label Poland alone. Iceland's names would come from the LMÍ **örnefni** dataset (which is already fetched and unimported, and would also fix unnamed peaks and unnamed waterfalls/springs); Sweden's from the Topo 10 `text` theme, which is in the Geotorget order we already have. This is the highest-value of the three. **Ditches.** Iceland's `vatnafar` has 93.6k (`yfirbordsvatn = 2`) and Poland's BDOT10k has `OT_SWRM_L`; both are deliberately excluded today. If they are ever wanted, note that Iceland's would have to be kept **out of the Strahler graph** — they are not part of the natural drainage network and would distort the stream ordering. **Sweden's reservoirs.** Topo 10 `mark` distinguishes 2634 "Anlagt vatten" and carries a `reglerat_vatten` flag. Both collapse to `lake` today because the shared `water` vocabulary has no `reservoir` and no other country can produce one — so this one is a vocabulary decision first, not an import.