Map and Table Calculation

^ operator

The exponential operator returns the result of a value a raised to a power b, i.e. ab.

Syntax

a ^ b

Input

a is the base value
Domain type: any Value domain
b is the exponent to which a is raised
Domain type: any Value domain

Output

^ returns: a real value
Domain: system domain Value

Notes:

Tips:

Usable in

MapCalc, TabCalc, Simple calculators

Examples

Pocket line calculator examples:

? 10^3

returns 1000

? POW(10,3)

returns 1000

? 8^(1/3)

returns 2.000

MapCalc example:

OutMap = InMapA ^ InMapB

 

InMapA

InMapB

OutMap

10 20 30
-40 50 60
70 ? 90
1 2 3
2 0 -1
? -2 0.5
10 400 27000
1600 1 0.0167
? ? 9.487

TabCalc example:

OutCol = InColA ^ InColB

 

InColA

InColB

OutCol

10

1

10

20

2

400

30

3

27000

-40

2

1600

50

0

1

60

-1

0.0167

70

?

?

?

-2

?

90

0.5

9.487

Applied example: exponential growth functions

In general, an exponential growth function is defined as:

An = A0 * (1 + perc/100)n

where:

An

is the amount after n years

A0

is the amount in year 0

perc

is the growth rate as a percentage per year

n

is the number of years

 

In ILWIS this function looks like:

An = A0 * (1 + perc/100)^ n

The expected total residential area after 4 years, of a residential area of 1136 ha with an estimated growth rate of 6% per year, is:

1136 * (1 + 6/100) ^ 4 = 1434

For the other landuse areas the results are:

 

LandUse

AreaHaY0

GrowPerc

AreaHaY4

Residential

1136

6

1434

Commercial

116

2

126

Industrial

173

3

195

Institutional

137

1

143

Recreational

77

2

83

Transportation

18

1

19

 

Where:

Column AreaHaY0 contains the areas in hectares for each land use class in year 0.

Column GrowPerc contains growth rates per year.

Column AreaHaY4 contains the areas of the land use classes after 4 years.

Notes:

See also:

+ /
- MOD