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) .


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


# Or the development version from GitHub:


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.

### Fastloc GPS data obtained from a green 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")


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

If you use the funtions 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

Current version

1.1.1 (10 June 2018)


output: html_notebook editor_options: chunk_output_type: inline

News for Package 'SDLfilter'

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 ( 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.


1.1.1 by Takahiro Shimada, 8 months ago

Report a bug at

Browse source code at

Authors: Takahiro Shimada

Documentation:   PDF Manual  

GPL-2 | file LICENSE license

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

Depends on ggplot2

See at CRAN