Auto-rotate flight plans to fly rough contoured grid according to terrain

[smathermather]

What type of Issue is this? (check all applicable)

• 🍕 Feature Request
• 🐛 Bug
• 📝 Documentation
• 🧑‍💻 Refactor
• ✅ Test
• 🤖 Build or CI
• ❓ Other (please specify)

Describe this Issue

• Flight plans are more efficient when rotated to roughly follow contours. Doesn't need to be as thorough as what this paper suggests, but can just follow the general terrain to avoid flight height changes along a collection path, ala:

Related but not directly relevant pull request: #395

Approach

Likely need to calculate an average azimuth from JAXA data, then use that to auto-rotate flight path. Probably enough to calculate azimuth on JAXA and then use a calculated global value for area of flight.

Advantage

Could be really useful, increase battery life, marginally improve photogrammetric output.

Disadvantage

Unsure if a bit of pre-optimization. May be really useful in high-relief contexts.

Inspiration

Gordon's post in ODM's community forum.