IdeaWell

Project ideas from Hacker News discussions.

Longest Straight Line Paths on Water or Land on the Earth (2018)

Original Article

Hacker News Discussion

📝 Discussion Summary (Click to expand)

Three prevalent themes in the discussion

  • Validation of the Reddit claim – Several commenters note that the authors’ algorithm confirmed the original Reddit user’s observation.

    ventana: “The paper is basically like this (spoiler alert): ‘Some random user on Reddit posted a picture claiming that this is the longest straight line path on water possible on the Earth. We implemented a smart algorithm to solve this problem, found the elevation data, ran our algorithm… yes, that random user was right.’”

  • Geometric explanation & visualization difficulty – The paths are described as great‑circle segments, comparable to the day/night line, and many users struggle to picture them on a globe.

    yorwba: “The day/light line is a great circle. The 'straight line paths' are great‑circle segments.”
    pdpi: “Does it help to point out that the water path looks suspiciously like the day/night line on a map?”
    comrade1234: “I opened Apple Maps in globe mode and I still have trouble visualizing the water path.”

  • Real‑world feasibility & obstacles – Contributors point out that the theoretical straight lines encounter physical barriers (mountains, rivers, ice, political borders) that make them impractical for driving or sailing without deviations.

    shrx: “Figure 9: Longest Drivable Straight Line Path on Earth. Walkable, maybe, but definitely not drivable (it crosses directly over the Alps, for example).”
    pbhjpbhj: “There might be icebergs or sandbars or rocks or volcanic activity or wars blocking the sailing route too.”
    OscarCunningham: “The one they give also crosses numerous rivers and lakes. For the strict version of the challenge where you literally can't cross water it's likely that the best solution is across Antarctica.”

🚀 Project Ideas

GreatCircle Explorer

Summary

  • Interactive 3D globe that computes and visualizes great-circle (straight‑line) paths on water or land, with toggleable layers for elevation, ocean depth, ice concentration, political borders, shipping lanes, and obstacle data.
  • Lets users instantly see why a path looks like a day/night line, switch between globe and flat map, and export the track as KML/GPX for further use.

Details

Key Value
Target Audience GIS enthusiasts, educators, travelers, puzzle solvers
Core Feature Compute great-circle routes and render them on a CesiumJS globe with rich geospatial overlays
Tech Stack CesiumJS, React, Node.js/Express, Python (GDAL/rasterio) for backend queries, PostgreSQL/PostGIS, AWS S3 for tile storage
Difficulty Medium
Monetization Hobby

Notes

  • Addresses comrade1234’s frustration: “I opened Apple Maps in globe mode and I still have trouble visualizing the water path.” and mrgriscom’s first‑person rendering request.
  • Provides a shareable link (like gcmap) so HN users can discuss specific paths and obstacle layers directly in comments.

StraightLine Route Planner

Summary

  • Web service that, given start/end points, generates a feasible route that stays as close as possible to the ideal great‑circle while avoiding user‑selected obstacles (e.g., land for a water path, ice, political borders, or non‑drivable terrain).
  • Returns GPX/KML with waypoints, total deviation distance, estimated travel time, and elevation profile.

Details

Key Value
Target Audience Sailors, pilots, hikers, adventurers, GIS analysts
Core Feature Obstacle‑aware route generation that minimizes deviation from a straight line, with deviation analytics
Tech Stack Python (NetworkX, rasterio, Turf.js), OpenStreetMap + OSRM, SRTM elevation data, React frontend, Deck.gl for map visualization, Node.js API
Difficulty High
Monetization Revenue-ready: Subscription $15/mo for high‑resolution routes and bulk API; free tier limited to low‑resolution samples

Notes

  • Directly answers metalman’s wish: “it would be interesting if it was a list of actual journeys with the sub lists of deviations required.”
  • Gives shrx a way to obtain walkable/drivable alternatives to the theoretically straight but impractical paths, sparking discussion on feasibility.

StraightLine Quest Platform

Summary

  • Community‑driven platform where users upload GPS tracks of their real‑world attempts to follow a straight line (walk, sail, drive, etc.).
  • System calculates deviation from the ideal great‑circle, awards badges for longest verified paths, hosts leaderboards, and provides discussion threads for each attempt.

Details

Key Value
Target Audience Explorers, hobbyists, geocachers, fitness enthusiasts
Core Feature Submit GPX/KML, compute % deviation, leaderboards, commentaries on obstacles encountered
Tech Stack Firebase (Auth, Firestore, Storage), React, Mapbox GL JS, Turf.js for geodesic calculations, Node.js Cloud Functions
Difficulty Medium
Monetization Hobby

Notes

  • Fulfills metalman’s idea of “a special club for the brutaly determined and persistant the ‘straight liners’.”
  • Builds on shrx’s reference to the Wikipedia Straight_line_mission article, giving users a place to share and verify their own missions, encouraging HN discussion and practical experimentation.

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