dt.steps: Determine temporal resolution

In the-Hull/TREX: Tree Sap Flow Extractor

Determine temporal resolution

Description

Performs minimum time step standardization, gap filling and start/end time selection. This function provides the option to select the minimum temporal step size of an is.trex object. Additionally, the user can define the start and end time of the series and select the minimum size under which gaps should be filled, using linear interpolation.

Time series have different temporal resolutions. This function provides the option to standardize the minimum time step by either performing a linear interpolation when the requested time step is smaller than the minimum time step of the series or average values when the requested time step is larger than the minimum time step of the series. Before this process, the entire time series is converted to a one-minute time step by applying a linear interpolation (excluding gap periods > \code{max.gap}).

Usage

dt.steps(input, start,
       end, time.int = 10, max.gap = 60,
       decimals = 10, df = FALSE)

Arguments

input	An is.trex-compliant (output) object
start	Character string providing the start time for the series. Format has to be provided in "UTC" (e.g., "2012-05-28 00:00" or Year-Month-Day Hour:Minute). Starting time should not be earlier than the start of the series.
end	Character string providing the start time for the series. Format has to be provided in "UTC" (e.g., "2012-06-28 00:50" or Year-Month-Day Hour:Minute). End time should be earlier than the end time and not later than that of the series.
time.int	Numeric value providing the number of minutes for the minimum time step. When time.int is smaller than the minimum time step of the series, a linear interpolation is applied. If time.int is larger than the minimum time step of the series values are averaged to the chosen value of time.int (after performing a linear interpolation to obtain a one-minute resolution).
max.gap	Numeric value providing the maximum size of a gap in minutes, which can be filled by performing a linear interpolation.
decimals	Integer value defining the number of decimals of the output (default = 10).
df	Logical; if TRUE, output is provided in a data.frame format with a timestamp and a value (\Delta T or \Delta V) column. If FALSE, output is provided as a zoo object (default = FALSE).

Value

A zoo object or data.frame in the appropriate format for further processing.

Examples

## Not run: 
input <- is.trex(example.data(type="doy"),
           tz="GMT",time.format="%H:%M", solar.time=TRUE,
           long.deg=7.7459,ref.add=FALSE)
in.ts <- dt.steps(input=input,start='2012-06-28 00:00',end='2012-07-28 00:00',
                   time.int=60,max.gap=120,decimals=6,df=FALSE)
plot(in.ts)
head(in.ts)

## End(Not run)

the-Hull/TREX documentation built on Feb. 15, 2024, 9:13 a.m.