Spherical linear interpolation between two positions: the point a given
fraction of the way along the great-circle arc joining them.
Usage
gc_interpolate(lat1, lon1, lat2, lon2, fraction)
Arguments
- lat1, lon1
Start positions, in decimal degrees.
- lat2, lon2
End positions, in decimal degrees.
- fraction
Fraction of the way from the start to the end, in [0, 1].
Value
A tibble with columns lat and lon, in decimal degrees.
References
Shoemake, K. (1985) Animating rotation with quaternion curves.
ACM SIGGRAPH Computer Graphics 19(3):245-254, for spherical linear
interpolation. doi:10.1145/325165.325242
Examples
# Halfway along a degree of latitude
gc_interpolate(43, -69, 44, -69, 0.5)
#> # A tibble: 1 × 2
#> lat lon
#> <dbl> <dbl>
#> 1 43.5 -69