... FORTRAN did not have the luxury of superscripts and subscripts -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of James R. Frysinger Sent: 15 January 2011 16:52 To: U.S. Metric Association Subject: [USMA:49523] Re: Screen size conundrum
Correction: E notation is not engineering notation. It is FORTRAN notation, since carried forth into other computer languages. Jim On 2011-01-15 1046, James R. Frysinger wrote: > I can find no examples of engineering (E) notation in the SI Brochure. > All of their examples are in terms of scientific notation (×10). NIST SP > 811 prefers scientific notation. > > Apart from that, Gene's preference might be fine for engineers and > scientists, but I cannot imagine it being used in advertisements meant > for public information. > > Jim > > On 2011-01-14 2339, [email protected] wrote: >> For Jim's sample, I would prefer "pixel density" of 20.84 E6 m^-2; >> keeping the prefix "milli" out of the denominator, retaining only the >> four original significant digits, and avoiding confusing of the >> "entity" (pixel) with the SI unit (m^-2), even though base 10 >> exponential notation (E6) is not universally established. >> >> ---- Original message ---- >>> Date: Fri, 14 Jan 2011 11:39:48 -0600 >>> From: "James R. Frysinger"<[email protected]> >>> Subject: [USMA:49516] Re: Screen size conundrum >>> To: "U.S. Metric Association"<[email protected]> >>> >>> Pixels are discrete, uniform (within one device) entities. Rather like >>> ladybugs. I think the proper unit is merely inverse square meters >>> (m^-2). If one is not averse to using prefixes in the denominator, then >>> large numerical values can be avoided. >>> >>> Sample: >>> "The display screen of my HP laptop is set to 1680 pixels by 1050 >>> pixels, for a total of 1 764 000 pixels. Its dimensions are 36.8 cm by >>> 23.0 cm, giving it an area of 846.40 cm2. Its pixel density then is 2084 >>> cm^-2." >>> >>> Note that in the above example, the result could have been given as >>> 20.84 mm^-2 (or 20.84/mm2). If one objects to using prefixes in the >>> denominator, then this would have been 20 840 000/m2, a rather large and >>> cumbersome number. Note that I have provided 4 digit precision here, >>> rather than 3 digit precision, despite the precision of the screen >>> dimensions. >>> >>> Personally, I prefer seeing the number of pixels in a square centimeter >>> or in a square millimeter. I have no great objection to prefixes in >>> denominators, especially when there are no units in the numerator. I can >>> visualize a square centimeter or square millimeter at least as easily as >>> I can visualize a square meter. But I can visualize 21 or 2100 much more >>> easily than I can visualize 21 000 000. >>> >>> By the way, one must distinguish among native resolution (or pixel >>> density) and those provided by software techniques. >>> >>> Jim >>> >>> On 2011-01-14 1059, [email protected] wrote: >>>> Michael, Jon, and Patrick, >>>> >>>> The "best" unit for TV screen area (size) is the coherent SI unit >>>> "meter squared." >>>> Flat screens of area about 1 m^2 and larger are already quite common. >>>> >>>> The "best" unit for TV pixel density is the unit "pixels per meter >>>> squared." >>>> (I hesitate to call "pixels/m^2" an "SI unit." How is "pixel" >>>> related to SI? >>>> >>>> Of course, SI prefixes may be applied to the numerators of each unit >>>> (preferably, excluding prefixes in the denominators). >>>> >>>> Gene. >>>> >>>> ---- Original message ---- >>>>> Date: Fri, 14 Jan 2011 07:00:14 -0500 >>>>> From: Jon Saxton<[email protected]> >>>>> Subject: [USMA:49509] Re: Screen size conundrum >>>>> To: "U.S. Metric Association"<[email protected]> >>>>> >>>>> I thought about this issue about 4 years ago. I think the best unit >>>>> for >>>>> measuring screen sizes is dm² but I expect an adverse reaction from >>>>> other members of this list. >>>>> >>>>> >>>>> On 2011-01-12 1858, Michael GLASS wrote: >>>>>> Dear People, >>>>>> >>>>>> There's a real problem with electronic screen sizes - all of them. >>>>>> This >>>>>> includes cameras, video cameras, computers, DVD players GPS >>>>>> monitors and >>>>>> television sets. >>>>>> >>>>>> >>>>>> 1 Because the screens are different shapes, there is no fixed >>>>>> relationship >>>>>> between the size of the screen and the measure given. >>>>>> >>>>>> 2 Even in cases where there is a fixed ratio between shape of the >>>>>> screen and >>>>>> the size of the screen, the increase in the size is not linear, >>>>>> but is >>>>>> related to the square of the number given. >>>>>> >>>>>> 3 As a result, power consumption on larger screen sizes is far >>>>>> higher than >>>>>> might be anticipated by looking at the screen size. For example, a >>>>>> 15 inch >>>>>> computer monitor is very nearly a 33% larger than a 13 inch model >>>>>> whereas 15 >>>>>> is just over 15% larger than 13. >>>>>> >>>>>> 4 With the issue of global warming, the power consumption of >>>>>> larger screens >>>>>> is a matter of increasing concern. >>>>>> >>>>>> 5 Even if you express screen sizes in metric terms the diagonal is >>>>>> still a >>>>>> misleading measure of the size of the screen. >>>>>> >>>>>> It seems to me that the best way to express the size of the screen >>>>>> is to >>>>>> give its area. So here is my conundrum: would it be better to >>>>>> express this >>>>>> size in square metres, square millimetres or square metres? What >>>>>> do others >>>>>> think? >>>>>> >>>>>> Michael Glass >>>>>> >>>>>> >>>>> >>>> >>>> >>>> >>>> >>> >>> -- >>> James R. Frysinger >>> 632 Stony Point Mountain Road >>> Doyle, TN 38559-3030 >>> >>> (C) 931.212.0267 >>> (H) 931.657.3107 >>> (F) 931.657.3108 >>> >> >> >> >> > -- James R. Frysinger 632 Stony Point Mountain Road Doyle, TN 38559-3030 (C) 931.212.0267 (H) 931.657.3107 (F) 931.657.3108
