localMin {hydroEvents}

Local minima

Description

Returns the index of local minima.

Usage

localMin(x)

Arguments

x

The data vector

Details

If values are repeated it returns the first index of occurrence. If the first value is repeated it is ignored as a local minima.

Value

Returns indices of local minima

Examples

# Find minima (with repeated values)
x = c(1, 2, 9, 9, 2, 1, 1, 5, 5, 1)
m = localMin(x)
plot(x, type = "l", lwd = 2, xlab = "", ylab = "", mgp = c(2, 0.6, 0))
points(m, x[m], pch = 16, col = "red")

# Find maxima (with repeated values)
x = c(1, 2, 9, 9, 2, 1, 1, 5, 5, 1)
m = localMin(-x)
plot(x, type = "l", lwd = 2, xlab = "", ylab = "", mgp = c(2, 0.6, 0))
points(m, x[m], pch = 16, col = "red")

# Minima in streamflow
m = localMin(dataBassRiver)
plot(dataBassRiver, type = "l", col = "steelblue", lwd = 2, ylab = "Flow (ML/d)",
   xlab = "Time index", mgp = c(2, 0.6, 0))
points(m, dataBassRiver[m], col = "red", pch = 16)

# Minima in quickflow
bf = baseflowA(dataBassRiver, alpha = 0.925)
qf = dataBassRiver - bf$bf
m = localMin(qf)
plot(qf, type = "l", lwd = 2, ylab = "Quickflow (ML/d)", xlab = "Time index", mgp = c(2, 0.6, 0))
points(m, qf[m], col = "red", pch = 16)

# Maxima in quickflow
bf = baseflowA(dataBassRiver, alpha = 0.925)
qf = dataBassRiver - bf$bf
m = localMin(-qf)
plot(qf, type = "l", lwd = 2, ylab = "Quickflow (ML/d)", xlab = "Time index", mgp = c(2, 0.6, 0))
points(m, qf[m], col = "red", pch = 16)