lag_difference: lag_difference

In jkennel/waterlevel: Well Water Level Analysis Tools

Description

Calculate differences for the dependent and independent variables and remove any NA values. This modifies the data.table in place.

Usage

lag_difference(dat, var_name = "wl", lag_space = 1, inverse = FALSE,
  remove_na = TRUE)

Arguments

dat	data that has the independent and dependent variables (data.table)
var_name	name of the column to lag (character)
lag_space	space between difference calculation in number of observations
inverse	whether the barometric relationship is inverse (TRUE means that when the barometric pressure goes up the measured water level goes down (vented transducer, depth to water), FALSE means that when the barometric pressure goes up so does the measured pressure (non-vented transducer)) (logical).
remove_na	remove NA values (logical)

Value

data.table with lagged differences

Examples

library(data.table)
datetime <- seq.POSIXt(as.POSIXct("2016-01-01 12:00:00"),
                       as.POSIXct("2016-01-05 12:00:00"), by='hour' )
baro <- sin(seq(0, 2*pi, length.out = length(datetime)))
wl <- 0.4 * baro
dat <- data.table(baro, wl, datetime)
lag_difference(dat, lag_space = 1, remove_na = FALSE)

jkennel/waterlevel documentation built on Dec. 1, 2019, 6:24 p.m.