## Utilities

Interesting and useful applications of {nvctr}

along_track_distance()

Compute the along-track distance from a great circle arc

altitude_azimuth_distance()

Calculate the altitude, azimuth and distance of B from A

cross_track_distance()

Compute the cross-track distance from a great circle arc

cross_track_intersection()

Calculate cross-track intersection

## References

R2xyz()

Find the three rotation angles about new axes in the xyz order from a rotation matrix

R2zyx()

Find the three angles about new axes in the zyx order from a rotation matrix

R_EL2n_E()

Find n-vector from the rotation matrix (direction cosine matrix) R_EL

R_EN2n_E()

Find n-vector from R_E

R_Ee()

Select the axes of the coordinate frame E

lat_lon2n_E()

Convert (geodetic) latitude and longitude to n-vector

n_E2R_EN()

Find the rotation matrix R_EN from n-vector

n_E2lat_lon()

Convert n-vector to latitude and longitude

n_EA_E_and_n_EB_E2p_AB_E()

Find the delta position from two positions A and B

n_EA_E_and_p_AB_E2n_EB_E()

Find position B from position A and delta

n_EB_E2p_EB_E()

Convert n-vector to cartesian position vector in meters

n_E_and_wa2R_EL()

Find R_EL from n-vector and wander azimuth angle

nvctr

nvctr: non-singular geographical position calculations

p_EB_E2n_EB_E()

Convert cartesian position vector in meters to n-vector

xyz2R()

Create a rotation matrix from 3 angles about new axes in the xyz order.

zyx2R()

Create a rotation matrix from 3 angles about new axes in the zyx order.

## Helpers

deg()

Convert angle in radians to degrees

rad()

Convert angle in degrees to radians.

unit()

Make input vector unit length, i.e. norm == 1