SDLfilter
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)
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.
-
dupfilter removes temporal and spatial duplicates.
-
ddfilter removes locations with high error.
-
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 turtledata(turtle)### Remove temporal and spatial duplicatesturtle.dup <- dupfilter(turtle)### Remove biologically unrealistic fixesturtle.dd <- ddfilter(turtle.dup, vmax=9.9, qi=4, ia=90, maxvlp=2.0)### Plot the locations on a map# unfilteredplotMap(turtle, point.size = 2, line.size = 0.5, axes.lab.size = 0)# filteredplotMap(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.