I'm not sure your note about only considering origin and destination for distance calculation is correct. (pointswithacrew.com)
Sturdy, lightweight, and compact the Bushnell Fusion ARC binocular laser rangefinder offers the complete package for distance calculation married with excellent optical viewing ability. (geekwrapped.com)
Some of the considerations that were important here were: considering «as the crow flies» versus plausible flight routes; whether minimising distance travelled would alone solve the problem; consideration of journey time (for example, whether direct or multiple flights might be needed); accuracy of complex distance calculations. (teachermagazine.com.au)