🧭 Outdoor GPS Calculators

📖 How to Use This Tool

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🎯 Destination Point Calculator

Purpose: Calculate coordinates at a specific bearing and distance from your position (line-of-sight navigation).

  • Start Latitude/Longitude: Your current GPS coordinates
  • Bearing: Direction in degrees (0° = North, 90° = East, 180° = South, 270° = West)
  • Distance: Distance in kilometers (can use decimals: 0.5 km = 500 meters)
  • Use My Location: Automatically fills in your current GPS position (requires permission)

Example: You're on a beach and spot a shark 500 meters offshore at bearing 270° (due West). Enter your location, bearing 270°, distance 0.5 km → calculates the shark's approximate coordinates for reporting to authorities.

📍 Route Distance Calculator

Purpose: Calculate total distance along a multi-point path (coastal patrol, property boundary, search pattern, etc.)

  • Enter each waypoint as: latitude,longitude
  • One waypoint per line
  • Minimum 2 points required
  • Calculates great-circle distance (shortest path on Earth's surface)

Example - Coastal Patrol Route:

-33.9258,18.4232
-33.9268,18.4245
-33.9275,18.4258
-33.9282,18.4270
⚠️ Important Notes:
  • Uses WGS-84 geodetic system (same as GPS devices)
  • Distances are approximate - terrain and elevation affect real-world travel
  • Always verify critical coordinates with official maps
  • South African coordinates are negative (Southern Hemisphere & East of Prime Meridian)
🔬 Technical: Great-Circle Distance & Haversine Formula

Great-circle arc: The shortest path between two points on a sphere (like Earth). Think airline routes that curve on a flat map ✈️🌍

Haversine formula: The mathematical formula used to calculate great-circle distance between two latitude/longitude points.

Are they the same? Yes, in practice. When someone says "great-circle distance" or "haversine distance," they mean the same result.

Technical note: Haversine assumes Earth is a perfect sphere. More advanced formulas (Vincenty, Karney) use an ellipsoid and are slightly more accurate over very long distances. For hiking, sailing, GPS outdoor apps, and these calculators → Haversine is the correct choice.

💡 Quick Tips:
  • Distance conversions: 0.1 km = 100m, 0.5 km = 500m, 1 km = 1000m
  • Common bearings: N=0°, NE=45°, E=90°, SE=135°, S=180°, SW=225°, W=270°, NW=315°
  • Typical use: Marine spotting (sharks, boats), property boundaries, search patterns, obstacle locations
  • Accuracy: Coordinates shown to 6 decimal places (±0.1 meter precision)

1️⃣ Destination Point

2️⃣ Route Distance (Waypoints)

Great-circle distance (WGS-84)

⚖️ Legal Information & Compliance (South Africa)

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MIT License

Copyright (c) 2026 George Blom (G.I.P.) (George in Plett)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

1. Disclaimer of Liability

This GPS calculator tool is provided "as is" without warranty of any kind, express or implied. The developer(s) and distributor(s) of this tool make no representations or warranties regarding:

Users assume all risk and liability for the use of this tool. The developer(s) shall not be liable for any direct, indirect, incidental, consequential, or punitive damages arising from the use or inability to use this tool, including but not limited to personal injury, property damage, or financial loss.

2. South African Legal Framework

2.1 Consumer Protection Act, 2008 (Act No. 68 of 2008)

In accordance with the Consumer Protection Act:

2.2 Electronic Communications and Transactions Act, 2002 (ECTA)

This tool complies with ECTA provisions:

2.3 Protection of Personal Information Act, 2013 (POPIA)

Privacy and data protection commitments:

3. Specific Use Cases & Warnings

🚨 Critical Safety Warnings

  • Not for Aviation: This tool is NOT approved for aviation navigation and must not be used for flight planning or in-flight navigation
  • Not for Marine Navigation: Not certified for marine navigation; use official nautical charts and approved navigation systems
  • Not for Emergency Services: Do not rely on this tool for emergency response, search and rescue, or life-safety applications
  • Not for Surveying: Not suitable for cadastral surveying, legal boundary determinations, or professional land surveying
  • Not for Military Use: Unauthorized for military or defense-related navigation purposes

3.1 Recreational Use

For hiking, geocaching, and outdoor recreation:

3.2 Protected Areas & Restricted Zones

Users must comply with South African legislation regarding:

4. Technical Limitations

5. User Responsibilities

By using this tool, you agree to:

6. Indemnification

Users agree to indemnify and hold harmless the developer(s), contributor(s), and distributor(s) from any claims, damages, losses, liabilities, and expenses (including legal fees) arising from:

7. Applicable Law & Jurisdiction

This disclaimer and any disputes arising from the use of this tool shall be governed by the laws of the Republic of South Africa. Users consent to the exclusive jurisdiction of South African courts for resolution of any disputes.

8. Severability

If any provision of this legal notice is found to be invalid or unenforceable under South African law, the remaining provisions shall continue in full force and effect.

9. Amendments

This legal notice may be updated periodically. Continued use of this tool constitutes acceptance of any amendments.

📞 Emergency Contacts (South Africa):
Emergency Services: 10111 (Police) / 10177 (Ambulance)
Mountain Rescue: 021 937 0300 (Western Cape Wilderness Search and Rescue)
National Sea Rescue: 087 094 9774

Last Updated: January 2026
Effective Date: January 2026

© 2026 George Blom (G.I.P.) (George in Plett)

Licensed under the MIT License