CIVIL ENGINEERING FORMULAS

CHAPTER 7

177

SURVEYING

FORMULAS

UNITS OF MEASUREMENT

Units of measurement used in past and present surveys are

For construction work: feet, inches, fractions of inches (m, mm)

For most surveys: feet, tenths, hundredths, thousandths (m, mm)

ForNational Geodetic Survey(NGS) control surveys: meters, 0.1, 0.01, 0.001 m

The most-used equivalents are

1 meter 39.37 in (exactly)  3.2808 ft

1 rod1 pole1 perch ft (5.029 m)

1 engineer’s chain100 ft100 links (30.48 m)

1 Gunter’s chain66 ft (20.11 m)100 Gunter’s links (lk) 4 rods mi

(0.020 km)

1 acre100,000 sq (Gunter’s) links43,560 ft^2 160 rods^2 10 sq

(Gunter’s) chains4046.87 m^2 0.4047 ha

1 rood acre (1011.5 m^2 )40 rods^2 (also local unit to 8 yd)

(5.029 to 7.315 m)

1 ha10,000 m^2 107,639.10 ft^2 2.471 acres

1 arpentabout 0.85 acre, or length of side of 1 square arpent (varies) (about

3439.1 m^2 )

1 statute mi5280 ft1609.35 m

1 mi^2 640 acres (258.94 ha)

1 nautical mi (U.S.)6080.27 ft 1853.248 m

1 fathom6 ft (1.829 m)

1 cubit18 in (0.457 m)

1 vara33 in (0.838 m) (Calif.), in (0.851 m) (Texas), varies

1 degree circle60 min3600 s 0.01745 rad

sin 10.01745241

(^1) 
360

331  3

(^3)  4 51  2
(^1) 
80

161  2