NEWS.md
In trajr: Animal Trajectory Analysis

Changes to the `trajr` package

Added some basic 3D trajectory functionality; see Traj3DFromCoords and all functions prefixed with Traj3D.
TrajAngles now returns NA for the angles before and after zero-length segments. Thanks to Valentin Baumann for identifying this bug. This change could potential cause problems with existing code, but such a problem would indicate a problem with the old analysis. The bug occurred because in base R, Arg(0) == 0, which is not correct. Various function that take means of TrajAngles now remove NA values.
Added function TrajFromTrjPoints to simplify operations such as removing zero-length segments from a trajectory.
Fix documentation of TrajDirectionalChange and TrajAngles. The documentation incorrectly stated that the number of angles returned was number of points - 1. It now states that the number of angles is number of points - 2 (which is number of segments - 1).
Fix bug in TrajFromCoords that incorrectly treated NA values in columns other than coordinates or time as an error.
Fix bug in TrajScale; yScale was being ignored.
Add some more named parameters to plot.Trajectory to avoid passing them to graphics::lines.
Add arg simConstantSpeed to TrajRediscretize and Traj3DRediscretize.
Add arg check.names to TrajsMergeStats.
Updated github continuous integration actions (using usethis::use_github_action("test-coverage") and usethis::use_github_action_check_release()). This change does not affect users

Allow the creation of trajectories with 0 points in TrajFromCoords.
Fixed bug in TrajSpeedIntervals: no intervals were being returned if the entire trajectory qualified as an interval.
Fix bug in plot.TrajSpeedIntervals: time (x-axis) didn't handle trajectories with a non-zero starting time.
Added functions to assist in simulating trajectories that are bounded or vary spatially in some way. The new functions are TrajInPolygon, TrajSplit, TrajMerge and TrajSplitAtFirstCrossing.
Added functions to calculate velocity and acceleration: TrajVelocity and TrajAcceleration. The documentation for TrajDerivatives has been updated to state that the acceleration returned is not really acceleration, rather it is change in speed over time.
Added argument diff to TrajSpeedIntervals to control how speed is calculated. Default is "backward" so the function is backwards-compatible, although "central" is usually a better choice.

Detect and report some invalid parameter values.
Altered handling of parameter readcsvFn to TrajsBuild to make it possible to use readr::read_csv without a wrapper function.
Added function TrajResampleTime to resample a trajectory to fixed step times.
Added parameters start.pt.pch and start.pt.col to plotting functions.
Added parameter dt to TrajTranslate
Fix vertical extents of rectangles in plot.TrajSpeedIntervals to handle non-default ylim values.
Added optional progressbar to TrajsMergeStats.
TrajsMergeStats now passes the arguments stringsAsFactors = FALSE to rbind. This prevents incorrect behaviour and the warning "invalid factor level, NA generated" if one or more of your statistics are characters.
Enhanced TrajRotate to allow absolute rotation and arbitrary origin of rotation.

Added correct citation.
Fixed: plot.TrajSpeedIntervals was not passing additional arguments (...) to plot.
Added: functions TrajDuration, TrajMeanVelocity, TrajTranslate.
Added translateToOrigin parameter to function TrajsBuild.