SDLfilter: dupfilter_qi – R documentation

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SDLfilter

dupfilter_qi

Filter temporal duplicates by quality index

Description

Function to filter temporal duplicates in tracking data by quality index.

Usage

dupfilter_qi(sdata = sdata, step.time = 0)

Arguments

sdata

A data frame containing columns with the following headers: "id", "DateTime", "qi". See the data turtle for an example. The function filters the input data by a unique "id" (e.g. transmitter number, identifier for each animal). "DateTime" is the GMT date & time of each location in class POSIXct or character with the following format "2012-06-03 01:33:46". "qi" is the quality index associated with each location fix. The input values can be either the number of GPS satellites or Argos Location Classes. Argos Location Classes will be converted to numerical values, where "A", "B", "Z" will be replaced with "-1", "-2", "-3" respectively. The greater number indicates a higher accuracy.

step.time

Consecutive locations less than or equal to step.time apart are considered temporal duplicates. Default is 0 hours.

Details

This function is a partial component of dupfilter, although works as a stand-alone function. It looks for temporal duplicates and retains a fix with the highest quality index.

Value

The input data frame is returned with temporal duplicates removed by the quality index.

Author(s)

Takahiro Shimada

References

Shimada T, Limpus C, Jones R, Hazel J, Groom R, Hamann M (2016) Sea turtles return home after intentional displacement from coastal foraging areas. Marine Biology 163:1-14 doi: 10.1007/s00227-015-2771-0