setBSWFUsed {photobiology} | R Documentation |
The "bswf.used" attribute
Description
Function to set by reference the "time.unit"
attribute of an
existing source_spct object
, and function to query its value.
Usage
setBSWFUsed(x, bswf.used = c("none", "unknown"))
getBSWFUsed(x)
Arguments
x |
a source_spct object. |
bswf.used |
a character string, either |
Details
Effective spectral irradiance, describes an estimate of the strength of the radiation towards eliciting a given response, frequently, but not only a biological response. The biological spectral weighting function, BSWF, used, can be for example that of the human eye, or an action spectrum, such as the erythema, or reddening of the human skin, action spectrum.
I_{BE}(\lambda) = I(\lambda) \times f_{BE}(\lambda)
where, I_{BE}(\lambda)
is the biologically effective spectral
irradiance, I(\lambda)
is the spectral irradiance
and f_{BE}(\lambda)
is one of many possible BSWF.
When the values stored in a source_spct
object have been multiplied
by those from a curve describing a certain response or effect, the
attribute "time.unit"
is set accordingly to track the transformation
applied to the data. When a spectral response data have been directly measured,
they should be stored in an object of class response_spct
as they
are expressed in actual response units, not
of class source_spct
expressed in irradiance units, even if weighted.
However, when like in the case of spectral
illuminance, the aim is technical measure of a light source,
class source_spct
should be used and the BSWF set in the metadata.
This attribute is normally set by the function or operator used to apply
the BSWF to spectral irradiance data, or set when the source_spct
object
is created.
Value
x
or the character
value stored in x
.
Note
Function setBSWFUsed()
alters x
itself by reference and in addition
returns x
invisibly. If x
is not a source_spct
, x
is not modified.
The behaviour of this function is 'unusual' in that the default for
parameter bswf.used
is used only if x
does not already have
this attribute set. Function getBSWFUsed()
returns the value to
which the attribute is set as a character
string and otherwise
NA
.
Examples
getBSWFUsed(sun.spct)