Wikidata:Property proposal/Viewpoint heading

Heading

Originally proposed at Wikidata:Property proposal/Commons

   Done: heading (P7787) (Talk and documentation)

Description	Direction of the camera or the viewer, measured as clockwise angle from the North, given in degrees, radians or other units. Mathematically it is direction of a vector from viewpoint location (stored in P1259), and in case of the images the vector should point towards the center of the image. Aliases: azimuth, clockwise angle from the North, camera heading, view direction
Represents	heading (Q4384217)
Data type	Quantity
Template parameter	one of "attributes" in c:template:Location
Domain	visual artworks: photograph (Q125191), painting (Q3305213), woodcut print (Q18219090), etc.
Allowed units	radian (Q33680), degree (Q28390), gradian (Q208528), ETC.
Example 1	@ Mihonomatsubara (Q64015956) → 67 degree (Q28390)
Example 2	@ To the transhipping place (Q79237814) → 67 degree (Q28390)
Example 3	@ M81444287 → 314 degree (Q28390)
Example 4	@ M51867633 → 231 degree (Q28390)
Planned use	planning to use it on Commons
See also	coordinates of the point of view (P1259)

Motivation

Commons template c:Template:Location stores camera locations and camera headings. We are planning to migrate that metadata to Structured Data on Commons using coordinates of the point of view (P1259) for the camera location, but still need a place to store the heading. Jarekt (talk) 15:55, 20 December 2019 (UTC)

Discussion

 Support I changed the datatype to quantity because we can use degree (Q28390) just like how we use height (P2048). Maybe someone can add some file examples? Multichill (talk) 17:36, 20 December 2019 (UTC)

Both examples were images with q-IDs and I added some random image without. --Jarekt (talk) 18:16, 20 December 2019 (UTC)

 Comment If we use units, the values can be other than 0-360. If the unit is gradian (Q208528) it should be 0-400 and if it is radian (Q33680) it should be 0-2π, etc. Ainali (talk) 17:49, 20 December 2019 (UTC)

Good idea about adding units. Thanks--Jarekt (talk) 18:26, 20 December 2019 (UTC)

 Comment It might be better to make this more general ("angle from North?") and use it as a qualifier only. I thought we had such a property already, but I can't easily find it. Thanks. Mike Peel (talk) 21:13, 20 December 2019 (UTC)

Viewpoint heading seems to be general enough for me. My intention was to only use it as qualifier to coordinates of the point of view (P1259), but I see that's not explicit in the proposal. @Jarekt: do you agree to focus on the qualifier part? I checked a long time ago and couldn't find any property to cover this need. Multichill (talk) 22:07, 20 December 2019 (UTC)

The problems with the current label are that "viewpoint" implies something is being viewed, and "heading" implies movement in that direction. Something like "Angle from North" would avoid those implications, and could then also be used more widely (although it might need to be caveated with "clockwise"). Thanks. Mike Peel (talk) 22:50, 20 December 2019 (UTC)

The term viewpoint heading was my attempt at making camera heading more general, so it can be applied to paintings and other non-photographic images. I was assuming that it is going to be a qualifier for coordinates of the point of view (P1259). I am also OK with making it more general, like heading with azimuth and clockwise angle from North aliases if we can come up with other situations we can use it. --Jarekt (talk) 03:19, 21 December 2019 (UTC)

Let's just label it "heading", add a bunch of aliases and a clear description. Multichill (talk) 11:35, 28 December 2019 (UTC)

Hanged the name to just "heading" --Jarekt (talk) 03:18, 30 December 2019 (UTC)

 Support I'd still prefer 'angle from north' to avoid the implication of moving in that direction, but I can live with this. Thanks. Mike Peel (talk) 20:53, 4 January 2020 (UTC)

 Support - Not just useful for Commons, i could also use this as a qualifier on coordinate location (P625). For example, the famous cover for Abbey Road (Q173643) is at 51.5324097,-0.1776726, but the viewport heading is around 320 degrees. Husky (talk) 11:38, 28 December 2019 (UTC)

@Husky: It should actually be a conflicting qualifier for coordinate location (P625) because coordinates of the point of view (P1259) should be used ;-) (changed it). Multichill (talk) 20:51, 4 January 2020 (UTC)

@Multichill:Ah, dang, i guess you're right. We have too many coordinate properties. I'll redo the ones my bot already did. Husky (talk) 20:44, 5 January 2020 (UTC

•  Comment I am dubious that we need more resolution that the existing 16-point compass rose available with direction relative to location (P654). Are there really that many cases where we will be specifying directions more precisely than the nearest 22.5° ? Note that we will also have properties for camera location and location of thing depicted? Jheald (talk) 21:01, 30 December 2019 (UTC)
  • @Jheald: I didn't know about that property, but I'm quite sure it got created before we had the quantity datatype. I don't like doing this with items like north-northeast (Q12599076). Right now more than 22.5° might be very precise, but we might as well have camera's in the future that include a very exact heading. Think of things like augmented reality and overlaying new and old photos to line up exactly. Multichill (talk) 20:40, 4 January 2020 (UTC)
    • We definitely need a property that can be very specific. The current metadata already has a higher detail than a 16-point compass, so why round that down if we have the data? And indeed, if we ever want to do something advanced like Photosynth (Q1848975) you need the specific metadata. Husky (talk) 22:41, 10 January 2020 (UTC)
•  Support I think this property can give some good value, especially when it allows high precision. For well photographed places, this extra metadata can make it easier to create panoramas and/or 3D images (where a 16-point compass rose is too low resolution to add value). Ainali (talk) 22:11, 30 December 2019 (UTC)
•  Support Moebeus (talk) 11:18, 7 January 2020 (UTC)