Wikipedia talk:WikiProject New Zealand/West Coast task force/Geography

Rivers mis-categorised

I've spotted that some (many?) rivers in Kahurangi are mis-categorised. The boundary between Tasman and Buller districts is somewhat random (which reflects that at the time the boundary was drawn, hardly a fair-skinned person would ever have set foot into the area, I suppose). User:Canley, would you be able to employ your GIS skills to spit out a list of what's wrong with Category:Rivers of the Tasman District and Category:Rivers of the West Coast, New Zealand? For example, the Heaphy River shows up as being in Tasman, which very clearly it isn't. If you could provide a Wikidata dump of what's in the wrong spot, I'd be happy to go through it and adjust things on Wikidata (district), on en.WP the stub tag and the category, and the respective category on Commons. Schwede66 02:24, 7 December 2021 (UTC)

Sure, no problem, sounds quite possible! I already have the rivers dataset and the district/region boundaries, so should be pretty easy to do a spatial query and compare it to Wikidata and the categories on the English Wikipedia and Commons. --Canley (talk) 04:29, 7 December 2021 (UTC)

OK, seems to have worked! Here are the results:

Rivers in Tasman District category located in Buller District

River article	District
Blackwater River (New Zealand)*	Buller District
Heaphy River	Buller District
Leslie River	Buller District
Montgomerie River	Buller District
Rahu River	Buller District
Roaring Lion River	Buller District

Rivers in West Coast Region category located in Tasman District

River article	District
Blackwater River (New Zealand)*	Tasman District
Buller River	Tasman District
Deepdale River	Tasman District
Matiri River	Tasman District

Note: Blackwater River (New Zealand) seems to be a disambiguation page with three rivers listed

@Schwede66: I haven't checked these thoroughly but there's only a few. Could be some errors with repeated names, or rivers in both regions. A lot of Wikidata items are missing P131s, I might use the query to populate these. --Canley (talk) 23:07, 7 December 2021 (UTC)

Canley, that's terrific! Thank you. I'll work through the lot, including splitting the dab page. Schwede66 01:49, 8 December 2021 (UTC)

No problem, happy to help! Let me know if you need any maps generated for confirmation, I can do these easily. For example, the article Deepdale River says "It is mostly in the West Coast Region of the South Island, but the lower part of the river is in the Tasman Region." I did a quick map from the LINZ data and also checked on OpenStreetMap and it appears, as the query suggests, that the river is entirely located in Tasman District (although it goes very close to the border). --Canley (talk) 03:25, 8 December 2021 (UTC)

All done. I've gone along the Tasman / Buller districts boundary (Lewis Pass to the sea) and can confirm that there are only two rivers crossing the boundary: the Maruia River and the Buller River. Those two rivers are correct both on WP, Commons and Wikidata. I'll still have to merge the various Maruia River WD items. Other than that, this has all been dealt with. Schwede66 21:47, 13 December 2021 (UTC)