log_derivative_spane: log_derivative_spane

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

Description

Function to calculate the derivative of the drawdown with respect to the derivative of log time using the approach proposed by Spane(1993) based on linear regression

Usage

log_derivative_spane(t, s, n = 2, 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

Spane, F. & Wurstner, S. DERIV: a computer program for calculating pressure derivatives for use in hydraulic test analysis Ground Water, 1993, 31, 814-824

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_spline, log_derivative

Examples

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_spane(ptest$t, ptest$s, n = 6)
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 Nov. 15, 2019, 8:10 p.m.