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) .

nvctr

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:

devtools::install_github("euctrl-pru/nvctr")

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

install.packages("nvctr")

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