Commands and Formulas

PERCENT CHANGE
(New-Old)/old

GREP
\ - esc special character

^ - at the beginning of a line

$ - at the end of a line
. - any character except return
(grouped expression)
\number -references grouped expression in the replace field
^[\r] -removes empty lines

GEOMETRY

Area of a circle = π * r2

Scale conversion for Population/m2 : Population/km2

Pop/m2 : Pop/km2
5 : 12.94994055
10 : 25.8998811
50 : 129.4994055
100 : 258.998811
250 : 647.4970275
500 : 1294.994055
1,000 : 2589.98811
10,000 : 25899.8811
50,000 : 129499.4055
100,000 : 258998.811
500,000 : 1294994.055
1,000,000 : 2589988.11

CONVERSIONS

Knots to MPH:
(x)1.150811228

Miles to Kilometer:
(x)0.621371

Excell
Dates: return number of days, months, years between two formatted dates
=DATEDIF(A1,B1,”d”)
d=days, m=months, y=years, md=difference in months inside months, yd=differnce in days inside year, ym=difference in months inside years

Concatinate and convert to text as in FIPS codes

=TEXT(A2,”00″)&TEXT(B2,”000″)