Wikidata talk:Coordinates tracking

If I see an article on English Wikipedia with coordinates, but with a category showing it is not here, how do I add it here? Be specific with instructions here, or a link to other instructions in Wikidata.--Dthomsen8 (talk) 14:44, 16 January 2014 (UTC)

Comparing coordinates

In Catalan Wikipedia we have already started to compare coordinates. We have ca:Categoria:Municipis amb coordenades a més de 5 km de les de Wikidata, included by a few infoboxes, and using it we have corrected more than 500 villages coordinates - most of them locally, but some tens or a few hundreds in Wikidata.

Now we are trying to expand the project to more infoboxes and even to our coord template.--Pere prlpz (talk) 21:04, 21 January 2014 (UTC)

French Wikipedia now has it built into Module:Coordinates (when the "wikidata" parameter is set to "true"). You can define the maximum acceptable distance between Wikidata and Wikpedia coordinates through the "maxdistance" parameter (default: 10 km). Pages that are above this threshold are categorized in fr:Catégorie:Page avec coordonnées différentes sur Wikidata. --Zolo (talk) 09:31, 7 March 2014 (UTC)

The distance should be based on dim or precision.

Say we have circle A with the Wikipedia coordinates in the center and dim as radius and circle B with the Wikidata coordinates in the center and precision as the radius. The Wikidata coordinates should be in circle A and the Wikipedia coordinates should be in circle B.

This is something we should be able to implement in lua.

@Zolo:, do you also have a category for Category:Coordinates not on Wikidata (Q15181099)? Multichill (talk) 20:40, 7 March 2014 (UTC)

Using the precision seems like a good idea, as long as it can be overridden by a customized parameter. And it would be trivial to implement in the French module. However a vast number of items apparently have their coordinates precision erroneously set to a 1000th of arcsecond. That should be fixed first. Also, I am nitpicking, but it is slightly inconsistent, as distances are logically computed in kilometers while precision is in degrees. One degree of longitude is much less in Sweden than in Ecuador.

I don't know what you call dim, but I think using Wikidata precision alone is enough. If the coordinates refer to the same thing in Wikipedia and Wikidata, the precisions should be equivalent.

fr.wikipedia does not have Category:Coordinates not on Wikidata (Q15181099) but it can easily be created if needed. --Zolo (talk) 22:09, 7 March 2014 (UTC)

Let's start with the easy part: Please enable Category:Coordinates not on Wikidata (Q15181099) on the French Wikipedia :-)

Now the harder part. We have two systems to implement the scale of something:

• Dim (from dimension) from mw:Extension:GeoData#Glossary: "approximate size of an object. Used by GeoData to restrict search and by Geohack for determining appropriate map zoom. The default unit of measurement is metres, although the km suffix may be appended to indicate kilometres."
• Precision in arcsecond used here at Wikidata.

Conversion between the two is possible. It's actually implemented in Pywikibot, see the function. It takes into account the location on the globe (Sweden vs Ecuador problem), but there I ran into a new problem (track in Bugzilla: 62105): What are the valid values for precision? You're not nitpicking, we need to have this cleared up before we sink deeper into the swamp of inconsistency.

Once that is all cleared up I can start running my new bot and import with the right precision. Multichill (talk) 11:31, 8 March 2014 (UTC)

• We now have fr:Catégorie:Page sans coordonnées Wikidata‎. Note that the French module allows customized queries like "search the coordinates of a the source of a river". If it does not find that, the page will be categorized in "wikidata coordinates missing" even if we have coordinates for the river mouth.
• I suppose precision could be converted in dim or scale to adjust geohack zooming level then. For categorizing pages, however, I do not think it is necessary. The purpose of the categories like "coordinates different in Wikidata" is just to find potential errors, and that does not need high precision. A precision in degreees cannot be designed to be very accurate anyway (in Stockholm it means at the same time 110 km North-South and 55 km East-West). To say it differently the data about the precision of the coordinates cannot be, well precise. That said, I definitely think we need a precise function to compute distances between two points. There is one in the French module, and it works for all globes supported by geohack. --Zolo (talk) 18:54, 8 March 2014 (UTC) + Zolo (talk) 07:59, 9 March 2014 (UTC)

In cawiki we are using "type" as a benchmark for comparison: 5k and 20km for type:city, 2km for type:railwaystation and 1000km for anything else. In spite of false positives, it is being useful to correct errors (in cawiki and in Wikidata) and the plan is to expand it to more types.--Pere prlpz (talk) 17:40, 1 October 2014 (UTC)

That seems like a viable solution. Actually, Lua infoboxes with better Wikidata support are now being deployed on fr.wikipedia, which should make maintenance finetuning easier. --Zolo (talk) 19:25, 7 October 2014 (UTC)

Re-import of coordinates from Wikidata to en: Wikipedia

I've started to import coordinates from Wikidata to enwiki, where appropriate. Although at the moment this looks like duplication, the addition of these tags to articles is intended to be the start of a process which will later allow data to be pulled directly from Wikidata, as we migrate the entire enwiki coordinate-tagging system to Wikidata in the long term.

I've tagged all of these with "source:wikidata" to avoid possible future confusion: see en:Sadowo, West Pomeranian Voivodeship for an example of a tagged article. Note in particular that these imported coordinates are all represented in degrees, to four decimal places, regardless of the precision of the original data. -- The Anome (talk) 07:24, 17 August 2014 (UTC)

Uh, what? I don't think that's the right approach. Better approach would be to update en:Template:coord missing to fetch the coordinates from Wikidata, or replace it with something like "coord Wikidata". That way we can already slowly move towards Wikidata. Multichill (talk) 08:32, 17 August 2014 (UTC)

That's what I intend to do eventually. However, we will need to move forward very slowly and carefully on this: the coordinate-tagging system on enwiki is very complex, there are a huge number of articles (over 870,000) that incorporate coordinates via a number of different access paths, including a lot of infoboxes maintained by different editors, and lots of editors are at the same time working on tagging and correcting coordinates using a variety of tools. For all these reasons, sudden change would be a bad idea, and we will need to maintain forward and backward compatibility for a long time. Marking these as "source:wikidata, display=title" is done for exactly those reasons: not only does this work at the moment without redefining the template, but these are such a simple case that they are ideal for being chosen to be the first tags to be migrated to pulling their coordinates from Wikidata, similar to your "coord Wikidata" proposal, once we start to change the template interface. -- The Anome (talk) 09:05, 17 August 2014 (UTC)

Instead of importing static values, I suggest using a template using Wikidata values. To avoid disturbing other users or other templates, as The Anome said, I suggest doing it only in articles without coordinates. In cawiki, we did it using the same template used to mark and categorize articles without coordinates, ca:template:cal coor.--Pere prlpz (talk) 17:02, 1 October 2014 (UTC)

I am indeed only doing it for articles currently without coordinates. However, there are real problems with just using transclusion without tighter integration into Wikipedia: for example, vandalism on the Wikidata coordinates will go un-noticed on the client wikis, since changes to transcluded Wikidata data do not show up on watchlists and are not visible in the article history. This isn't just a problem with coordinates: it's a general problem with cross-wiki transclusion. Until there is a proper versioning/alert system for correlating changes on Wikidata with changes on Wikipedia, I'd prefer to keep the static copies of the coordinates for the time being. In the long run, this does not hold us up at all: the template can easily be modified later to ignore the coordinates given there in favour of those on Wikidata. -- The Anome (talk) 13:26, 10 October 2014 (UTC)

Northernmost point and so

We have properties for extreme latitude and longitude points. It would be useful to use them to automatically check that main coordinates are inside extreme coordinates. Here, they weren't. It would be a simple way to check some coordinates, since extreme coordinates and main coordinates are likely to come from unrelated sources.--Pere prlpz (talk) 16:17, 9 October 2014 (UTC)

This is a bit more gnarly than it appears at first sight. Some entities cross the 180 degree meridian, throwing simple algorithms that assume latitude and longitude exist on a plane-like topology into disarray. Some countries -- like France -- have territories which extend way beyond the boundaries of their mainland, again making simple box models useless. -- The Anome (talk) 13:31, 10 October 2014 (UTC)

import tool

Is there a simple tool that could be linked from "import it" at the end of case 1: data exists in Wikipedia? I deleted some wrong coordinates this morning as Wikidata seemed to be the source that was feeding Wikiminiatlas the wrong location, but can't work out how to import the right ones. Thanks. --ScottDavis (talk) 09:28, 24 August 2016 (UTC)

Updates

Hello all, are there updates on this project? We're interested in wikipedia/wikidata coordinates, finding a fair number of disagreements. It would be great if there were tools to check agreement between wikipedia and wikidata, and flag issues for user intervention if they cannot be fixed automatically. Bjohas (talk) 16:52, 3 June 2017 (UTC)