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

Original article
arxiv.org|168 points|49 comments|by joebig|Aug 30, 2026

Analysis of the Maximum Linear Trajectories Across Terrestrial and Aquatic Surfaces (2018)

This document provides a comprehensive overview of the research paper hosted on arXiv under the identifier 1804.07389.

📄 Document Metadata

AttributeSpecification
Primary AuthorsRohan Chabukswar and Kushal Mukherjee
arXiv Identifier1804.07389
Mathematical SubjectHistory and Overview (math.HO)
MSC Classification65K10
Digital Object Identifierhttps://doi.org/10.48550/arXiv.1804.07389

🎯 Research Objective

The core of this study revolves around solving two symmetrical optimization challenges. The authors seek to determine the absolute longest distance a straight line can be drawn on the Earth's surface under two different constraints:

  1. The Aquatic Path: The maximum distance one can sail in a straight line without making contact with any landmass.
  2. The Terrestrial Path: The maximum distance one can drive in a straight line without crossing a significant body of water.

The Mathematical Challenge

The authors note that this is not a simple calculation. The problem is characterized as an optimization task that becomes predictable chaotic due to:

  • The scattered distribution of islands and lakes.
  • The fractal nature of global coastlines.

In mathematical terms, the goal is to find: max⁡(d) subject to Path∩Boundary=∅\max(d) \text{ subject to } \text{Path} \cap \text{Boundary} = \emptysetmax(d) subject to Path∩Boundary=∅


🛠 Methodology

To solve these complex spatial problems, the researchers employed a specific computational strategy.

"In this paper we present a methodology for calculating the two paths using the branch-and-bound algorithm."

Algorithmic Logic

The branch-and-bound approach allows the system to prune large sections of the search space that cannot possibly contain the optimal solution, focusing only on the most promising trajectories.

# Conceptual logic of the search process
def find_longest_path(surface_type):
    best_distance = 0
    while search_space_exists:
        branch = split_search_area()
        if bound(branch) > best_distance:
            best_distance = evaluate_path(branch)
    return best_distance

Process Visualization


📅 Submission Timeline

The paper underwent several iterations before reaching its final form:

  • v1: Submitted on Monday, 9 Apr 2018 (Size: 5,683 KB)
  • v2: Revised on Saturday, 5 May 2018 (Size: 5,683 KB)
  • v3: Revised on Thursday, 28 Jun 2018 (Size: 5,654 KB)
  • v4: Final revision on Monday, 2 Jul 2018 (Size: 5,654 KB)

🌐 Access and Integration

Users can access the full text via several formats:

  • PDF: Standard document view.
  • HTML: Experimental Experimental web-based view.
  • TeX Source: Available under the site's license.

Conceptual Map of Earth Paths

External Tooling & Discovery

The arXiv platform integrates various discovery tools to enhance the research experience:

  • Bibliographic Tools: Bibliographic Explorer, Connected Papers, and scite.ai for smart citations.
  • Code & Data: Links to alphaXiv, CatalyzeX Code Finder, and Replicate demos.
  • Recommenders: Influence Flower for mapping related academic impact.

🧪 About arXivLabs

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  • Openness: Encouraging community-driven feature development.
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If you have a concept for a tool that would benefit the arXiv community, the platform encourages collaborative contributions.