CogoKit is 10 coordinate-geometry calculators, a 61-page reference library, 4 long-form guides, 330 practice questions and 61 fully worked problems. It exists because the computations a survey crew runs every day — closing a traverse, solving a curve, reducing a level loop, deciding which foot a coordinate is in — are badly served on the open web, and because the reference material that governs them is largely public domain and deserves to be explained rather than resold.
Where the material comes from
Two bodies of public-domain federal work underpin most of the reference library. The Bureau of Land Management's Manual of Surveying Instructions for the Survey of the Public Lands of the United States (2009) is the authority on the Public Land Survey System, and the National Geodetic Survey's publications are the authority on datums, heights and coordinate systems. Both are works of the United States government, both are free to adapt, and both are cited on every page that draws on them. That citation is not a formality — it is how you check whether this site is telling you the truth.
The calculators are tested against worked examples published in state departments of transportation's survey manuals, and against the exact identities the BLM Manual and the Federal Register define — a quarter-quarter section is exactly forty acres, the US survey foot is exactly 1200/3937 meter, a one-degree curve by the arc definition has a radius of 5729.578 feet. Where a fixture could be built either from a textbook's rounded table or from an exact closed form, the exact form was used, because a rounded table can hide a systematic error and a surd cannot.
What it deliberately does not do
- It does not reproduce the reference material supplied during the Fundamentals of Surveying examination. That document belongs to the exam provider, and you will have it on screen during the exam in any case.
- It does not teach any state's boundary law. Boundary questions here are limited to the nationally applicable principles — the PLSS, the commonly taught ordering of conflicting title elements, proportionate measurement — and name no statutes and no cases.
- It does not send anything you type anywhere. Every calculation runs in your browser. There is no server to send it to.
- It does not replace a licensed surveyor. A computed number is a check on your own work, not a professional opinion and not a sealed document.
On the exam, and on names
The Fundamentals of Surveying exam is developed and administered by the National Council of Examiners for Engineering and Surveying. This site names that exam because naming it is the only way to say what the practice material is for. Not affiliated with or endorsed by NCEES. NCEES® is a registered mark of the National Council of Examiners for Engineering and Surveying. Its specifications and examinee materials come from the council itself, and nothing here substitutes for them.
Corrections
Every number on this site was computed and checked, and some of them are still wrong — that is the nature of a few hundred worked problems. If you find an error, the most useful thing you can do is say which page and what you got instead.