Property talk:P2043
Documentation
measured dimension of an object
| Represents | length (Q36253), length overall (Q2358152) | ||||||||||||
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| Data type | Quantity | ||||||||||||
| Template parameter | "length" in w:en:template:infobox lake | ||||||||||||
| Domain | Any object with spatial extent (note: this should be moved to the property statements) | ||||||||||||
| Allowed values | According to this template:
All positive one-dimensional values with a length unit
According to statements in the property:
When possible, data should only be stored as statements0 ≤ 𝓧 ≤ not applicable | ||||||||||||
| Allowed units | Instances of: unit of length zeptometre (Q3270676), attometre (Q6003257), femtometre (Q208788), picometre (Q192274), nanometre (Q178674), micrometre (Q175821), millimetre (Q174789), centimetre (Q174728), decimetre (Q200323), metre (Q11573), kilometre (Q828224), foot (Q3710), inch (Q218593), mile (Q253276), yard (Q482798), nautical mile (Q93318), decametre (Q848856), thousandth of an inch (Q1165799), light-year (Q531), astronomical unit (Q1811), parsec (Q12129), yoctometre (Q3221356), centimillimetre (Q20706220), decimillimetre (Q20706221), hectometre (Q844338), megametre (Q1054140), gigametre (Q854546), terametre (Q3267417), petametre (Q3277919), exametre (Q3277907), zettametre (Q3277915), yottametre (Q10543042), Li (Q654875), zhàng (Q12170198), chi (Q2963205), Li (Q56277910), furlong (Q494083), chain (Q552299), base pair (Q145911), pixel (Q355198), légua de 18 ao grau (Q113613200), amino acid (Q8066), bit (Q8805), byte (Q8799), kilobit (Q3194304), kilobyte (Q79726), megabit (Q3332814), megabyte (Q79735), gigabit (Q3105497), gigabyte (Q79738), terabit (Q1152323), terabyte (Q79741), petabit (Q1152074), petabyte (Q79744), exabit (Q1195111), exabyte (Q79745), zettabit (Q1140444), zettabyte (Q79747), yottabit (Q1140577), yottabyte (Q79752), ronnabit (Q115485168), ronnabyte (Q115280832), quettabit (Q115485169), quettabyte (Q115277430), character (Q3241972) or verst (Q207733) | ||||||||||||
| Example | Trans-Siberian railway (Q58767) → 9,289 kilometre AA battery (Q1195592) → 49.85 millimetre | ||||||||||||
| Tracking: same | no label (Q32085220) | ||||||||||||
| Tracking: differences | no label (Q55283009) | ||||||||||||
| Tracking: usage | Category:Pages using Wikidata property P2043 (Q20989811) | ||||||||||||
| Tracking: local yes, WD no | Category:Length not in Wikidata, but available on Wikipedia (Q21037900) | ||||||||||||
| See also | width (P2049), height (P2048), area (P2046), volume as quantity (P2234), perimeter (P2547), event distance (P3157), thickness (P2610), duration (P2047), diameter (P2386), vertical depth (P4511), number of pages (P1104) | ||||||||||||
| Lists |
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| Proposal discussion | Proposal discussion | ||||||||||||
| Current uses |
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List of violations of this constraint: Database reports/Constraint violations/P2043#Units
List of violations of this constraint: Database reports/Constraint violations/P2043#Entity types
List of violations of this constraint: Database reports/Constraint violations/P2043#Scope, SPARQL
List of violations of this constraint: Database reports/Constraint violations/P2043#Conflicts with P31, SPARQL
Constraints
[edit]Discussion
[edit]What about using as distance between points?
[edit]Avatar6 (talk) 07:58, 16 April 2016 (UTC)
- @Avatar6: Good question, see for instance its usage on marathon (Q40244). 42.195 km is not the dimension of the object “marathon”. It is the distance between the start and finish line of a marathon. And while the English alias “distance” might perhaps allow such a statement, this is not the case for the German aliases which only cover physical dimensions of an object. What to do? —MisterSynergy (talk) 08:04, 5 August 2016 (UTC)
- Indeed, I can see a case for splitting length and distance. We have many specialised properties, e.g. distance from Earth (P2583), located on linear feature (P795), vehicle range (P2073), angular distance (P2212), apoapsis (P2243), wheelbase (P3039), clearance (P2793), stroke (P2557), takeoff roll (P2430) for distance or length, but only the one generic. The English description, "measured dimension of an object" also strongly implies it should not be used for distance. Thryduulf (talk) 00:36, 9 August 2016 (UTC)
- The distinction between dimension and distance was even made during P2043’s proposal, but somehow it got lost. Shall I just go to property proposal to ask for a distance property? —MisterSynergy (talk) 05:29, 9 August 2016 (UTC)
- Go for it. Thryduulf (talk) 12:30, 9 August 2016 (UTC)
- The distinction between dimension and distance was even made during P2043’s proposal, but somehow it got lost. Shall I just go to property proposal to ask for a distance property? —MisterSynergy (talk) 05:29, 9 August 2016 (UTC)
- Indeed, I can see a case for splitting length and distance. We have many specialised properties, e.g. distance from Earth (P2583), located on linear feature (P795), vehicle range (P2073), angular distance (P2212), apoapsis (P2243), wheelbase (P3039), clearance (P2793), stroke (P2557), takeoff roll (P2430) for distance or length, but only the one generic. The English description, "measured dimension of an object" also strongly implies it should not be used for distance. Thryduulf (talk) 00:36, 9 August 2016 (UTC)
Relative lengths
[edit]Some objects are not defined with an absolute length (with a defined unit of length), but instead are defined with lengths expressed as ratios (i.e. the unit of length is arbitrary, but relative to another length measurement).
For now it's impossible to specify a correct unit of length for such cases.
We should have another more generic property for "relative length", with a numeric value, either:
- a number and a dimensionless unit ("%", "perthousand", "ppm", ...) or
- a dimensionless number (the unspecified unit is implicitly 1)
and optional qualifiers to specify what is the reference of length:
- a "relative measurement" (or "axis") qualifier specifying which other measurement is as a reference length - this element may be a directly measurable physical property on some axis ("width", "height", "depth"...) or a statistic dimension (like "average"), or computed dimensions (like "square root" of surfaces or "cubic root" of volumes); its absence means the implicit measurement axis for linear objects (segments or curved arcs) with a measurable total length.
- an additional "computed from" qualifier (for computed dimensions) - whose value would be based on another measurement, like "surface" (when the relative dimension is "square root"), or "volume" (when the relative dimension is "cubic root")
- an additional "of" (or "reference") qualifier ("page"...) indicating the nature of the measured object of reference - it may be a specific part of the object, or another object (container, neighbour), or a set of objects (for statistic dimensions like "average" or computed dimensions like "square root"), its absence means the described oject itself
- other qualifiers may be needed to scope the reference to more specific sets (or classes) of objects, notably for statistic dimensions "of" sets of objects, such as dates (year, period, since, until...), "in" (geographic region, ethnic population or other properties applicable to instances of such classes of objects if we don't have a specific class defined with that precise property, like ages...) or exclusions ("not in", "except"...)
This also applies to other kind of measurements (surface, volume, weight) which are also often relative to objects, but whose units are not directly convertible (by an constant numeric ratio), even if they are measurements in the same dimension, unless we can specify a relative reference.
If we want to avoid specifyng all these qualifiers, and use directly the "length" property, then one way to do that is to allow creating new unit elements (with a required identical dimension = "length" here). These units can then specify as properties the same qualifiers described above. This will apply for example to volumes (e.g. "tea spoon" in cooking, whose absolute measurement in square meters or litres is not precise, but estimated, and may vary according to scoping usages specified as qualified properties of the "tea spoon" element).
Any element in Wikidata that has a measured dimension could be used as a unit (e.g. an object that has a known "length" could be used as a unit for the value to give to the "length" property.
If the specified unit element (e.g. "Earth") has several properties in the same required dimension (e.g. "width" and "height") we can still specify a length value as a number, and a unit="Earth" with the "relative measurement" qualifier to select that property of "Earth" (such as "average radius", "average diameter", "circumpherence", but selecting "surface" or "volume" would not be correct because they are in different dimensions): in that case the indicated unit ("Earth") is invalid without this qualifier (like "relative measurement"="average radius")
But if this becomes a common measurement unit, it will be best to create a new unit element (like "Earth average radius") whose "nature" (instance of) is "length unit" (itself defined with the correct "dimension"="length" property) so that we can, specify a "length" = (value: 2, unit: "Earth average radius") and no needed qualifier. As well we can createa new unit element "tea spoon volume" with property "nature"="volume unit" (itself defined with the correct "dimension"="volume" property) so that we wan correctly specify a "quantity" = (value:2, unit: "tea spoon volume") in a cooking recipe (where the quantities can have a value expressed in one of several dimensions like volume, weight, or counted units).
Verdy p (talk) 15:19, 13 May 2019 (UTC)
- Pardon. I can't imagine use cases. And why can't you use some strange items as units (like "Earth average radius") in property of absolute length? --Infovarius (talk) 09:14, 15 May 2019 (UTC)
on paintings
[edit]See Wikidata_talk:WikiProject_sum_of_all_paintings#length_(P:P2043)_on_paintings. --- Jura 12:44, 15 November 2021 (UTC)