BlayaSoft / Field Notes

Field notes on land navigation

Practical guides to MGRS, map reading, terrain analysis and getting a TAK network running — written by the developer of Tactical GPS.

18 JUL 2026

How to pass your land nav course: a system, not talent

Land nav fails more candidates than any other field event — and almost always for the same five reasons. Pace count, plotting discipline, attack points, aiming off, night navigation, and a two-week practice plan that works in any park.

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18 JUL 2026

What is viewshed analysis? See what you can see from anywhere

A viewshed shows exactly which terrain is visible from any point — the ridge-top view without the climb. How the algorithm works, what hunters, ham operators and SAR teams use it for, and the honest limits of 30-meter elevation data.

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18 JUL 2026

TAK on iPhone: set up a free OpenTAKServer in an afternoon

Live team positions on everyone's map, with the free open-source TAK server: install on a cheap VPS or Raspberry Pi, open four ports, enroll your iPhone with one QR scan — plus the firewall mistakes that cause 90% of failed connections.

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18 JUL 2026

How to read MGRS coordinates in 5 minutes

The Military Grid Reference System looks cryptic — 33T XJ 65490 44120 — until someone walks you through its four parts. Here's the whole system, from grid zones to 1-meter precision, with the mistakes everyone makes once.

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Next up: offline map apps for iPhone, compared honestly.