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
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
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))
