Using coins for scale is discouraged as it will require people unfamiliar with them to look up the dimensions or guess, both of which defeat the purpose of the object in the first place. Coins can also reinforce a geographical bias, and some coins' designs are copyrighted.
Ideally, a photograph should include a ruler with the subject (example) or an added scale marking.
SI ("metric") units are the most commonly used worldwide (see meter and centimeter).
Photograph taken by Mark A. Wilson (Department of Geology, The College of Wooster). [1]
Licentie
Public domainPublic domainfalsefalse
Ik, de auteursrechthebbende van dit werk, geef dit werk vrij in het publieke domein. Dit is wereldwijd van toepassing. In sommige landen is dit wettelijk niet mogelijk; in die gevallen geldt: Ik sta iedereen toe dit werk voor eender welk doel te gebruiken, zonder enige voorwaarden, tenzij zulke voorwaarden door de wet worden voorgeschreven.
{{Information |Description={{en|1=Heavy mineral layers (dark) in a quartz beach sand (Chennai, India).}} |Source=Original photograph |Author=Photograph taken by Mark A. Wilson (Department of Geology, The College of Wooster). |Date=May 2008 |Permission= |o