echogram (version 0.1.3)

navigation.hac: Compute bearing, navigated distance and speed

Description

This function computes navigation course (bearing), navigated distance, time diference and navigation speed between GPS fixes in position data imported from an HAC file.

Usage

navigation.hac(pos)

Value

A data frame with seven variables:

time.cpu

date and time from the computer CPU during data acquisition.

lon

longitudes.

lat

latitudes.

bearing

navigation course between two consecutive GPS fixes.

navdist

navigated distance between two consecutive GPS fixes.

time.dif

time difference between two consecutive GPS fixes.

navspeed

navigation speed between two consecutive GPS fixes.

Arguments

pos

geographic position data from an HAC file, as imported with position.hac.

Author

Héctor Villalobos

Details

The bearing and navigated distance are computed with functions bearingRhumb and distVincentyEllipsoid from package geosphere. This function is intended to be called inside read.echogram, rather than being used directly.

See Also

position.hac, bearingRhumb, distVincentyEllipsoid.

Examples

 hacfile <- system.file("hac", "D20150510-T202221.hac", package="echogram")
 pos <- position.hac( hacfile )
 pos
 pos2 <- navigation.hac(pos)
 pos2