Filtering Satellite-Derived Locations

Functions to filter GPS and/or Argos locations. The provided filters remove temporal and spatial duplicates, fixes located at a given height from estimated high tide line, and locations with high error as proposed in Shimada et al. (2012) and Shimada et al. (2016) .


Overview

SDLfilter contains a variety of functions to screen GPS and/or Argos locations, and to plot them on a map.

Installation

install.packages("SDLfilter")
 
# Or the development version from GitHub:
install.packages("devtools")
devtools::install_github("TakahiroShimada/SDLfilter")

Usage

There are three main filtering functions.

  1. dupfilter removes temporal and spatial duplicates.

  2. ddfilter removes locations with high error.

  3. depthfilter removes fixes located at a given height from estimated high tide line (e.g. locations on land).

Please see the help pages and Shimada et al. (2012, 2016) for more details.

library(SDLfilter)
 
### Fastloc GPS data obtained from a green turtle
data(turtle)
 
### Remove temporal and spatial duplicates
turtle.dup <- dupfilter(turtle)
 
### Remove biologically unrealistic fixes 
turtle.dd <- ddfilter(turtle.dup, vmax=9.9, qi=4, ia=90, maxvlp=2.0)
 
### Plot the locations on a map
# unfiltered
plotMap(turtle, point.size = 2, line.size = 0.5, axes.lab.size = 0)
 
# filtered
plotMap(turtle.dd, point.size = 2, line.size = 0.5, axes.lab.size = 0,
        bgmap = "satellite", sb.line.col = "white", sb.text.col = "white")

References

If you use the function ddfilter, please cite

Shimada T, Jones R, Limpus C, Hamann M (2012) Improving data retention and home range estimates by data-driven screening. Mar Ecol Prog Ser 457:171-180 http://dx.doi.org/10.3354/meps09747

If you use the functions dupfilter or depthfilter, please cite

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

Current version

1.2.1 (19 February 2019)

News


output: html_notebook editor_options: chunk_output_type: inline

News for Package 'SDLfilter'

Version 1.2.1 (2019-02-19)

  • amended "plotMap" in accordance with the ggsn update to version 0.5.0.

Version 1.2.0 (2019-02-18)

  • added a mew function "distance_filter". This function removes fixes located beyond a given threshold distance.
  • fixed bugs in the example codes.
  • amended "plotMap" in accordance with the ggmap update to version 3.0.0.

Version 1.1.1 (2018-06-10)

  • fixed minor bugs in the est.maxvlp function. The values estimated using the previous version would not have been affected by the changes. In the previous version, when sample size is too small (i.e. <6 fixes) or inner angles could not be estimated (e.g. two consecutive locations with the same coordinates), the function ceased with warning messages. These errors are now avoided by exuding those fixes from the estimation process.

Version 1.1.0 (2018-04-27)

  • added a new function (plot.map) to plot locations.
  • updated vignette.

Version 1.0.0 (2018-02-08)

  • First official release.

Reference manual

It appears you don't have a PDF plugin for this browser. You can click here to download the reference manual.

install.packages("SDLfilter")

1.2.1 by Takahiro Shimada, 4 months ago


https://github.com/TakahiroShimada/SDLfilter


Report a bug at https://github.com/TakahiroShimada/SDLfilter/issues


Browse source code at https://github.com/cran/SDLfilter


Authors: Takahiro Shimada


Documentation:   PDF Manual  


GPL-2 | file LICENSE license


Imports sp, raster, trip, data.table, geosphere, ggmap, gridExtra, ggsn, stats, maps

Depends on ggplot2


See at CRAN