On Wednesday, March 07, 2007 6:01 PM [GMT+1=CET], Ken Hornstein <[EMAIL PROTECTED]> wrote:
> Strictly speaking, data is the plural of datum, and should be used > with a plural verb (like facts). However, there has been a growing > tendency to use it as an equivalent to the uncountable noun > information, followed by a singular verb. This is now regarded as > generally acceptable in American use, and in the context of > information technology. The traditional usage is still preferable, > at least in Britain, but it may soon become a lost cause. > Within the context of GPS I have always seen people refer to the > plural > of "datum" as "datums" (e.g., http://www.gpsinformation.net); I have > _never_ seen anyone refer to multiple GPS datums as "data". Several > online dictionaries say for datum, "plural: data or datums", and at > least one reference I found says "In rare instances, the plural > datums may be used, specifically when datum refers to a reference or > standard value". The problem, as I see it, is that the Latin word 'datum' with its plural 'data' has, since its incorporartion into English, diverged into two quite different meanings, one of which makes no sense to me. Being used, as a mathematician, to the use of "data" to mean a set of numbers, I feel uncomfortable with the current use of "datum" in GPS and allied topics. I believe this started out with the "OS Datum" which specified that the place from which altitdue was measured by the Ordnance Survey was the mean high water spring tide level in a specific location (or something like that). I was perfectly happy with that - it was a given single item of information and I could accept "datum" as a proper word for it. But to extend that use to call a mathematical model of the Earth's surface a "datum" strikes me as flying in the face of linguistic sense. It's not a datum, it's an infinite set of data with a three-dimensional structure. Mike Stevens narrowboat Felis Catus III web-site www.mike-stevens.co.uk Defend the waterways. Visit the web site www.saveourwaterways.org.uk
