# interpolateTime: Interpolate a trajectory In move: Visualizing and Analyzing Animal Track Data

## Description

This function allows to interpolate trajectories. It does this on the basis of a simple interpolation, depending on the `spaceMethod` that is specified.

## Usage

 `1` ```interpolateTime(x, time, spaceMethod=c('euclidean','greatcircle','rhumbline'),...) ```

## Arguments

 `x` a `move` or `moveBurst` object. `time` either a number of locations (class `numeric`), a time interval (class `difftime`) or a vector of timestamps (class `POSIXct`) at which the interpolation should be done. See 'Details'. `spaceMethod` a character that indicates the interpolation function (euclidean, great circle or along the rhumb line) to be used to generate the new locations. `...` Currently not implemented.

## Details

In the argument `time`:
- number of locations: refer the total number of locations that the resulting track will have distributed equally over time. E.g. if `time=200`, the resulting track will have 200 points interpolated at a constant time interval.
- time interval: refers to the time interval at which a location should be interpolated. E.g. if `time=as.difftime(10, units="mins")` a location will be interpolated every 10 mins.
- vector of timestamps: the timestamps of this vector have to be in ascending order, and within the time range of the track.

## Value

Move-class object of the interpolated locations.

## Author(s)

Bart Kranstauber & Anne Scharf

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18``` ```data(leroy) ## providing the number of locations plot(leroy[100:150,], col="red",pch=20) points(mv <- interpolateTime(leroy[100:150,], time=500, spaceMethod='greatcircle')) ## providing a time interval plot(leroy[100:150,], col="red",pch=20) points(mv2 <- interpolateTime(leroy[100:150,], time=as.difftime(10, units="mins"), spaceMethod='greatcircle')) ## providing a vector of timestamps plot(leroy[100:150,], col="red",pch=20) ts <- as.POSIXct(c("2009-02-13 10:00:00", "2009-02-13 12:00:00", "2009-02-13 14:00:00", "2009-02-13 16:00:00","2009-02-13 18:00:00","2009-02-13 20:00:00", "2009-02-13 22:00:00","2009-02-14 00:00:00","2009-02-14 02:00:00", "2009-02-14 04:00:00","2009-02-14 06:00:00", "2009-02-14 08:00:00", "2009-02-14 10:00:00"), format="%Y-%m-%d %H:%M:%S", tz="UTC") points(mv3 <- interpolateTime(leroy[100:150,], time=ts, spaceMethod='greatcircle')) ```

move documentation built on Sept. 11, 2018, 5:06 p.m.