ndvi_derivatives {sephora} | R Documentation |
Calculates derivatives of idealized NDVI
Description
Provides function expression of derivatives of an idealized NDVI curve fitted through a harmonic regression model
Usage
ndvi_derivatives(amp, pha, degree, L)
Arguments
amp |
numeric vector specifying amplitude parameter |
pha |
numeric vector specifying phase angle parameter |
degree |
integer. What derivative's degree should be calculated?
|
L |
integer giving the number of observations per period |
Details
This function returns the derivatives of , with respect
to
, when
has the representation:
,
where and
are substituted by the vectors
amp
and phase
, respectively. The degree of the derivative is given by the
argument degree
.
Value
A function expression
Note
For historic reasons, we ended up using the name ndvi_derivatives
for this function, but it can be used to calculate derivatives of any function
expression defined through amp
, pha
, degree
and L
.
See Also
phenopar
, phenopar_polygon
, haRmonics