Traverse closure and area calculator
Type or paste one course per line. The misclosure, precision ratio, area and plot update as you type.
Bearings like N 45 30 15 E 120.50 or S68°05'35"W 472.68. Azimuths like 248 05 35 472.68. Decimal degrees work too.
Enter at least two courses to see the closure.
- Area
- Perimeter
- Error in northing (Σ latitudes)
- Error in easting (Σ departures)
- Courses
| # | Bearing | Azimuth | Distance | Latitude | Departure | Northing | Easting |
|---|
How the closure is worked out
Each course is split into a latitude (its north–south part) and a departure (its east–west part). For a traverse that returns to its starting point, both columns should sum to zero. What is left over is the error of closure.
The area is computed from the coordinates of the corners (the coordinate, or shoelace, method), starting at 0, 0 and following the courses in order.
Worked example
The sample is a four-sided boundary from a surveying textbook. Its courses total 1,347.57 ft. The latitudes sum to +0.083 ft and the departures to +0.074 ft, so the misclosure is √(0.083² + 0.074²) = 0.111 ft and the precision is 1,347.57 ÷ 0.111, about 1:12,100. The figure encloses about 2.36 acres.
What this page leaves to the app
- Balancing the traverse by the Compass (Bowditch) or Transit rule, and the adjusted area.
- Curve legs, link traverses between two control points, and sideshots.
- Saving the job and its points, and exporting CSV, DXF or a PDF report.
Questions
What precision ratio is acceptable?
It depends on the standard you are working to. Many state minimum standards for boundary surveys ask for 1:5,000 to 1:10,000 or better, with tighter ratios for urban work. Check the standard that governs your survey.
Is the area adjusted?
No. This page reports the area of the figure exactly as entered, closed by a straight line from the last point back to the start. The COGO app balances the traverse by the Compass (Bowditch) or Transit rule first and reports the area of the adjusted figure.
Can I enter azimuths instead of bearings?
Yes. A line that starts with N or S is read as a quadrant bearing. A line that starts with a number is read as an azimuth, clockwise from north. You can mix both in one traverse.
Does it handle curves?
Not on this page. Enter the chord bearing and chord distance for a quick closure check; the area will then miss the segment between chord and arc. The app takes curve legs directly (radius, arc length, left or right) and includes the segment in the area.
Is my data sent anywhere?
No. The calculation runs in your browser. Nothing you type leaves your device, and the page has no analytics or tracking.