Units

Wikipedia: https://en.wikipedia.org/wiki/Units_of_measurement
Wikipedia: https://en.wikipedia.org/wiki/System_of_measurement

Mass noun

Wikipedia: https://en.wikipedia.org/wiki/Mass_noun

RDF and Units

Units of measurement can be expressed with RDF, RDFS, and OWL.

CSVW and Units

See: CSVW, Tool Support for Units

Tool Support for Units

Spreadsheet tools:

  • Specify units in each column heading (e.g. "time [[s]]","speed [[m/s]]")
  • Extra column per column for units (e.g. "time","time unit","speed","speed unit")
  • CSVW: Columns have URIs, which are objects that can have subjects and predicates (for XSD types; metadata (author, date, rdfs:label "time"@en"), and possibly units of measure)

Unit and/or precision-aware calculations:

Storage formats:

  • [ ] Spreadsheet formats do not have unit of measure support.
  • CSV does not have unit of measure support.
  • JSON does not have unit of measure support.
  • RDF vocabularies support units of measure:
    • CSVW supports units of measure.
    • JSON-LD supports units of measure.

Binary Prefixes

Table of Binary Prefixes (adapted from: https://en.wikipedia.org/wiki/Binary_prefix)
Text Symbol Scalar (base 10) Scalar (base 1000) Scalar (base 1e1)
kilo k 1000 1000**1 1e3
mega M 1000000 1000**2 1e6
giga G 1000000000 1000**3 1e9
tera T 1000000000000 1000**4 1e12
peta P 1000000000000000 1000**5 1e15
exa E 1000000000000000000 1000**6 1e18
zetta Z 1000000000000000000000 1000**7 1e21
yotta Y 1000000000000000000000000 1000**8 1e24

See also: SI Prefixes

Metric System

Wikipedia: https://en.wikipedia.org/wiki/Metric_system
Wikipedia: https://en.wikipedia.org/wiki/Outline_of_the_metric_system

SI Prefixes

Wikipedia: https://en.wikipedia.org/wiki/Metric_prefix
Table of SI Prefixes (adapted from: https://en.wikipedia.org/wiki/Template:Common_metric_prefixes and https://en.wikipedia.org/wiki/Binary_prefix)
Text Symbol Scaling Factor Scaling Factor (e)
pico p 0.000000000001 1e-12
nano n 0.000000001 1e-9
micro μ 0.000001 1e-6
milli m 0.001 1e-3
centi c 0.01 1e-2
deci d 0.1 1e-1
(none) (none) 1 1e0
deca da 10 1e1
hecto h 100 1e2
kilo k 1000 1e3
mega M 1000000 1e6
giga G 1000000000 1e9
tera T 1000000000000 1e12
peta P 1000000000000000 1e15
exa E 1000000000000000000 1e18
zetta Z 1000000000000000000000 1e21
yotta Y 1000000000000000000000000 1e24

See also: Binary Prefixes

SI Distance Units

metre

Wikipedia: https://en.wikipedia.org/wiki/Metre
Wikipedia: https://en.wikipedia.org/wiki/Meter
Abbr: m
The metre is the length of the path travelled by light in vacuum during a time interval of 1/299792458 of a second

SI Volume Units

litre

Wikipedia: https://en.wikipedia.org/wiki/Litre
Abbr: L

SI Mass Units

kilogram

Wikipedia: https://en.wikipedia.org/wiki/Kilogram
gram
Wikipedia: https://en.wikipedia.org/wiki/Gram
Abbr: g

SI Time Units

second

Wikipedia: https://en.wikipedia.org/wiki/Second #TODO
Abbr: sec
Abbr: s
microsecond
Wikipedia: https://en.wikipedia.org/wiki/Microsecond #TODO
Abbr: TODO
millisecond
Wikipedia: https://en.wikipedia.org/wiki/Millisecond #TODO
Abbr: ms
minute
Wikipedia: https://en.wikipedia.org/wiki/Minute
Abbr: min
Abbr: m
hour
Wikipedia: https://en.wikipedia.org/wiki/Hour
Abbr: hr
Abbr: hrs
Abbr: h
day
Wikipedia: https://en.wikipedia.org/wiki/Day
Abbr: d
  • Conversion: 1 day == 24 hours
  • Conversion: 1 day == 1440 minutes
  • Conversion: 1 day == 86400 seconds
  • Rotational definition: 1 day == one complete planetary rotation
week
Wikipedia: https://en.wikipedia.org/wiki/Week
Abbr: wk
Abbr: wks
Abbr: w
month
Wikipedia: https://en.wikipedia.org/wiki/Month
Abbr: mon
Abbr: mons
Abbr: m
  • A month contains either 28 (Feb; 29 on a leap year), 30, or 31 days.
  • https://en.wikipedia.org/wiki/Thirty_days_hath_September
  • Two hands of knuckles with peaks and valleys together:
    • start with an outside knuckle
    • up (peak; knuckle) – 31 days
    • down (peak; knuckle) – 30 day (except for February, which has 28/29)
year
Wikipedia: https://en.wikipedia.org/wiki/Year
Abbr: yr
Abbr: yrs
Abbr: y
  • Conversion: 1 year == 365.25 days (1 leap day/4.0)
  • Conversion: 1 year == 365 days
  • Conversion: 1 year == 8760 hours
  • Conversion: 1 year == 525600 minutes
  • Conversion: 1 year == 31536000 seconds
  • Rotational definition: 1 year == 1 complete revolution around our singular planetary star: the sun.

SI Frequency Units

hertz

Wikipedia: https://en.wikipedia.org/wiki/Hertz
Abbr: Hz
  • TODO: cycles per time
  • TODO: em.py

SI Electric Current Units

ampere

Wikipedia: https://en.wikipedia.org/wiki/Ampere
Abbr: A # TODO
Abbr: amp

# TODO

volt

Wikipedia: https://en.wikipedia.org/wiki/Volt
Abbr: V # TODO

# TODO frequency / current relation

SI Power Units

SI Temperature Units

celsius

Wikipedia: https://en.wikipedia.org/wiki/Celsius
Abbr: C
  • Water (H2O) freezes at 0 degrees celsius.
  • Water (H20) boils at 100 degrees celsius.
  • [ ] celsius / kelvin relation

kelvin

Wikipedia: https://en.wikipedia.org/wiki/Kelvin
Abbr: K

SI Amount Units

SI Luminous Intensity Units

candela

Wikipedia: https://en.wikipedia.org/wiki/Candela
Abbr: cd

SI Data Units

bit

Wikipedia: https://en.wikipedia.org/wiki/Bit
Abbr: b

A bit can be 1 or 0.

  • A bit may indicate set containment (e.g. True or False, Black or White) [Set Theory]

  • A bit may be part of an ordered set of bits which ascribe left-to-right (little endian) or right-to-left (big endian) place values to each binary digit:

    1 2 4 8   # little endian
0 1 0 1   # == 0 + 2 + 0 + 8 == 9 (base 10)

8 4 2 1   # big endian
0 1 0 1   # == 0 + 4 + 0 + 1 == 5 (base 10)

  • See also: Information Theory > Shannon bit (Shannon entropy)

byte

Wikipedia: https://en.wikipedia.org/wiki/Byte
Abbr: B
  • Conversion: 1 byte == 8 bits
  • Storage vendors use powers of ten (e.g. MB, GB, TB) to describe storage capacity; and also binary prefixes (kilo, mega, giga, tera, peta, exa, zetta).
  • Many/most software programs use powers of two and binary prefixes (e.g. MiB, GiB, TiB) to describe e.g. partition and file sizes.
  • On-disk file sizes are often larger than the file content because of file allocation tables, redundancy, block size and allocation; but may be smaller after compression/deduplication.
Table of Bytes and Binary Prefixes
unit derivation value
nibble 2**2 bits 4 bits
byte 2**3 bits 8 bits
octet 2**3 bits 8 bits
word size

CPU

register width

(in bits)

8+, 16, 24, 32, 64 bits

32 bits (x86, ARM)

64 bits (x86_64, ARM 64)
kibibyte (KiB)

2**10 bytes

1024**1 bytes

 1024 bytes
kiloyte (KB)

1e3 bytes

1000**1 bytes

 1000 bytes
mebibyte (MiB)

2**20 bytes

1024**2 bytes

 1048576 bytes
megabyte (MB)

1e6 bytes

1000**2 bytes

 1000000 bytes
gibibyte (GiB)

2**30 bytes

1024**3 bytes

 1073741824 bytes
gigabyte (GB)

1e9 bytes

1000**3 bytes

 1000000000 bytes
tebibyte (TiB)

2**40 bytes

1024**4 bytes

 1099511627776 bytes
terabyte (TB)

1e12 bytes

1000**4 bytes

 1000000000000 bytes
pebibyte (PiB)

2**50 bytes

1024**5 bytes

 1125899906842624 bytes
petabyte (PB)

1e15 bytes

1000**5 bytes

 1000000000000000 bytes
exbibyte (EiB)

2**60 bytes

1024**6 bytes

 1152921504606846976 bytes
exabyte (EB)

1e18 bytes

1000**6 bytes

 1000000000000000000 bytes
zebibyte (ZiB)

2**70 bytes

1024**7 bytes

 1180591620717411303424 bytes
zettabyte (ZB)

1e21 bytes

1000**7 bytes

 1000000000000000000000 bytes
yobibyte (YiB)

2**80 bytes

1024**8 bytes

 1208925819614629174706176 bytes
yottabyte (YB)

1e21 bytes

1000**8 bytes

 1000000000000000000000000 bytes

Imperial units

Wikipedia: https://en.wikipedia.org/wiki/Imperial_units
Wikipedia: https://en.wikipedia.org/wiki/English_units

Imperial units may refer to either English units (ended in 1824) or US customary units (e.g. gram, ounce, gallon, pound, foot, mile).

Imperial Distance Units

inch

Wikipedia: https://en.wikipedia.org/wiki/Inch
Abbr: in
yard
Wikipedia: https://en.wikipedia.org/wiki/Foot
Abbr: yd
mile
Wikipedia: https://en.wikipedia.org/wiki/Mile
Abbr: mi
Abbr: m

Imperial Volume Units

teaspoon

Wikipedia: https://en.wikipedia.org/wiki/Teaspoon
Abbr: t
Abbr: tsp.

dram

Wikipedia: https://en.wikipedia.org/wiki/Dram_(unit)

tablespoon

Wikipedia: https://en.wikipedia.org/wiki/Tablespoon
Abbr: T
Abbr: Tbsp.

fluid ounce

Wikipedia: https://en.wikipedia.org/wiki/Fluid_ounce
Abbr: fl oz
Abbr: oz

pint

Wikipedia: https://en.wikipedia.org/wiki/Pint
Abbr: pt

quart

Wikipedia: https://en.wikipedia.org/wiki/Quart
Abbr: qt

gallon

Wikipedia: https://en.wikipedia.org/wiki/Gallon
Abbr: gal

keg

Wikipedia: https://en.wikipedia.org/wiki/Keg

Imperial Mass Units

gram

Wikipedia: https://en.wikipedia.org/wiki/Gram
Abbr: g

ounce

Wikipedia: https://en.wikipedia.org/wiki/Ounce
Abbr: oz

pound

Wikipedia: https://en.wikipedia.org/wiki/Pound
Abbr: lb
Abbr: lbm

ton

Wikipedia: https://en.wikipedia.org/wiki/Ton
  • Conversion: 1 ton == 2000 pounds
  • Conversion: 1 kilo- ton == 1000 tons
  • Colloqial: half ton truck refers to a minimum towing or hauling capacity; not the curb weight of a vehicle.
  • Conversion: 1 tonne (metric ton) == 1000 kg == 2204 pound
  • Conversion: 1 long ton == 2240 pound
  • Conversion: 1 short ton == 2000 pound

US customary units

Wikipedia: https://en.wikipedia.org/wiki/United_States_customary_units

Common US Fluid Conversions:

Industry Units

Freight

Fuel