log_derivative_spline: log_derivative_spline

In khaors/pumpingtest: R Package for the analysis and evaluation of pumping tests

log_derivative_spline

Description

Function to calculate the derivative of the drawdown with respect to the derivative of log time using the interpolation of the measured points with spline

Usage

log_derivative_spline(t, s, n = 20, return.pos = T, log = T)

Arguments

t	Numeric vector with the time
s	Numeric vector with the drawdown
n	Number of points where the derivative is calculated
return.pos	Logical flag to return only the positive values of the log-derivative (default = TRUE)
log	Logical flag to indicate that natural logarithm (a log to the base e) is used in the derivative calculation (default = TRUE). Logarithm to the base 10 is used if FALSE.

Value

A list with

• x: Numeric vector with the x coordinates where the log-derivative is evaluated

• y: Numeric vector with the value of the log-derivative

Author(s)

Oscar Garcia-Cabrejo [e-mail]

References

Renard, P.; Glenz, D. , Mejias, M. Understanding diagnostic plots for well-test estimation, Hydrogeology Journal, 2008, 17, 589-600

See Also

Other log_derivative functions: log_derivative_bourdet, log_derivative_central, log_derivative_horner, log_derivative_kernelreg, log_derivative_locpol, log_derivative_lokern, log_derivative_lpridge, log_derivative_smoothspline, log_derivative_spane, log_derivative

Examples

# Load test data
data(boulton)
t <- boulton$t
s <- boulton$s
ptest <- pumping_test('Well1', Q = 0.03, r = 20, t = t, s = s)
#
dptest.sp <- log_derivative_spline(ptest$t, ptest$s, n = 30)
plot(t, s, type="p", log="xy", ylim = c(1e-3,2))
points(dptest.sp$x, dptest.sp$y, col = "red")

khaors/pumpingtest documentation built on June 10, 2025, 4:53 a.m.