Map and Table Calculation

NDVI( ) function

Returns Normalized Difference Vegetation Index (NDVI) values, i.e. (b-a)/(b+a). NDVI values are a measure for the presence and condition of green vegetation.

Syntax

NDVI(Value a, Value b)

Input

Value a is the satellite band containing visible or red reflectance values
Domain type: an Image domain
Value b is the satellite band containing near-infrared reflectance values
Domain type: an Image domain

Output

NDVI returns: a value
Domain: system domain Min1to1
Value range: [-1,1]

Notes:

Tip:

When the definition symbol = is used, a dependent output map or dependent output column is created; when the assignment symbol := is used, the dependency link is immediately broken after the output map/column has been calculated.

Usable in

MapCalc, TabCalc, Simple calculators

Examples

Pocket line calculator examples:

? NDVI(46,78)

returns 0.258

MapCalc example:

OutMap = NDVI(TMBand3,TMBand4)

 

TMBand3

TMBand4

OutMap

18 25 28
? 53 44
80 92 73
28 30 34
39 44 55
? 71 175
0.217 0.091 0.097
? -0.092 0.111
? -0.129 0.411

TabCalc example:

OutCol = NDVI(InColA,IncolB)

 

InColA

InColB

OutCol

18

28

0.217

25

30

0.091

28

34

0.097

?

39

?

53

44

-0.092

44

55

0.111

80

?

?

92

71

-0.129

73

75

0.411