getTrends: Get Trends

View source: R/getTrends.R

getTrendsR Documentation

Get Trends

Description

Extract the trend results.

Usage

getTrends(Stations = "All", Snames = "All", sig.level = 0.05)

Arguments

Stations

a vector of the station identifiers on which to do the flow adjustment.

Snames

a vector of the response variables on which to do the flow adjustment.

sig.level

the alpha level of the test. If the attained p-value of the test is less than sig.level, then the null hypothesis of no trend is rejected and the trend is classes as "up" or "down."

Value

A data frame of the requested trend tests having these columns:

Station

the station identifier.

Response

the response variable name.

Type

the type of trend test.

NumYears

the number of years for the trend test.

NumSeasons

the number of seasons. Set to NA for the Tobit trend test.

Nobs

the number of observations used in the test.

RepValue

the representative value of the response variable. See Note.

Trend

the trend expressed as the average rate in Response units per year

Trend.pct

the trend expressed as the average rate in percent change per year

P.value

the attained p-value of the test.

Trend.dir

an indicator of the trend. Trend.dir is "none" if the attained p-value is greater than sig.level, "up" if the attained p-value is less than sig.level and Trend is positive, and "down" if the attained p-value is less than sig.level and Trend is negative. For the seasonal Kendall test, when there are many tied values, the results from the trend test and the trend may not agree, in these cases Trend.dir will be "*."

Note

The representative value is the median from a sample of the data taken to represent a reasonably uniform sampling over time and throughout the year. For the seasonal Kendall test, it is the median of the data, for the Tobit test, it is the median of the data sampled as for a seasonal Kendall test.


USGS-R/restrend documentation built on Oct. 11, 2022, 6:10 a.m.