Rhumb
Constant-course lines.
A rhumb line keeps one compass course all the way, and these tools find its course and distance between two points and the destination along a constant course, on the ellipsoid. Mariners and pilots planning constant-heading legs use them. Start with rhumb line distance and course. The pitfall is using a rhumb line for a long east-west route at high latitude, where it can be far longer than the shortest path.
Planning and education aid. Not for primary navigation. Full disclaimer
I want to find the distance and course of a rhumb line
- Rhumb line distance and course
The constant course and distance of the rhumb line (loxodrome) between two points on the ellipsoid, and how much longer it is than the shortest route.
I want to find where a constant course takes me
- Destination on a constant course (rhumb line)
Where a constant course (rhumb line, loxodrome) for a given distance ends on the ellipsoid; a rhumb that would cross a pole stops there.