# The n-vector Approach to Geographical Position Calculations using an Ellipsoidal Model of Earth

The n-vector framework uses the normal vector to the Earth ellipsoid (called n-vector) as a non-singular position representation that turns out to be very convenient for practical position calculations. The n-vector is simple to use and gives exact answers for all global positions, and all distances, for both ellipsoidal and spherical Earth models. This package is a translation of the 'Matlab' library from FFI, the Norwegian Defence Research Establishment, as described in Gade (2010) .

## Overview

The `nvctr` package implements the n-vector approach to geographical position calculations using an ellipsoidal model of Earth as described in (Gade 2010).

Implementations in various computer languages can be found at the n-vector page (Navigation Group 2010).

## Installation

You can install the development version of `nvctr` from GitHub with:

or the CRAN version (when this package will land to CRAN):

## Usage

`nvctr` can be used to solve geographical position calculation like (example numbers refer to the ones in the vignette):

• Calculate the surface distance between two geographical positions (Example 5).
• Find the destination point given start point, azimuth/bearing and distance (Example 8).
• Find the mean position (center/midpoint) of several geographical positions (Example 6).
• Find the intersection between two paths (Example 9).
• Find the cross track distance between a path and a position (Example 10).

## References

Gade, Kenneth. 2010. “A Non-Singular Horizontal Position Representation.” Journal of Navigation. https://doi.org/10.1017/S0373463309990415.

Navigation Group, FFI. 2010. “The N-Vector Page.” https://www.navlab.net/nvector/.

# nvctr 0.1.1

• Submission to CRAN.

# Reference manual

install.packages("nvctr")

0.1.4 by Enrico Spinielli, a year ago

https://github.com/euctrl-pru/nvctr

Report a bug at https://github.com/euctrl-pru/nvctr/issues

Browse source code at https://github.com/cran/nvctr

Authors: Enrico Spinielli [aut, cre] , EUROCONTROL [cph, fnd]

Documentation:   PDF Manual