Bearing & Distance Traverse Tool

Walks a metes-and-bounds description leg by leg: quadrant bearings and distances to coordinates, closure error and precision ratio, shoelace area — with optional GeoJSON/WKT export when anchored to a lat/lon. Runs entirely offline; the traverse persists in this browser via localStorage.

Use limits: This checks the arithmetic of a description; it is not a survey. Bearings in a deed are relative to that deed's basis of bearings (grid, true, or an assumed line) — walking them here on an assumed north is fine for "does this close and how big is it," not for staking anything. Curved boundaries entered as chord bearing + chord distance close correctly but understate the boundary length and misstate area slightly; deeds with significant curves belong in COGO software. Record boundaries belong to a licensed land surveyor.
Starting Point

The point of beginning's real-world position. Planar offsets are mapped to lat/lon on a local tangent plane — sub-centimeter at parcel scale.

Legs (quadrant bearing + distance)
#Quad°′″Distance (ft)End NEnd E

"N 45°30′00″ E, 231.50 ft" → Quad NE, 45 / 30 / 00, 231.50. Due north/east/south/west: 0° or 90° in a matching quadrant (e.g. due East = NE 90°).

How the Numbers Are Derived

Traverse math

Each quadrant bearing converts to an azimuth from north: NE → θ, SE → 180°−θ, SW → 180°+θ, NW → 360°−θ. Each leg advances the coordinates by ΔN = d·cos(az), ΔE = d·sin(az). Closure error is the straight-line distance from the final computed point back to the point of beginning; the precision ratio is perimeter ÷ closure, expressed 1:X. Area is the planar shoelace formula on the traverse polygon (closed to the start point), so a misclosure slightly distorts area — another reason to care about the ratio.

What the precision ratio means

1:X says the traverse missed closing by one part in X of its length. Rules of thumb: modern boundary surveys run 1:10,000 and better; older deeds and rural descriptions commonly check out around 1:5,000; worse than about 1:3,000 usually means a transcription error — a transposed digit, a dropped leg, or a bearing read from the wrong quadrant — rather than sloppy original surveying. When a description won't close, try flipping the quadrant on the most suspicious leg first; it's the most common typo.

Anchored export

With an anchor lat/lon at the point of beginning, planar offsets map to geographic coordinates using the local ellipsoidal radii: Δlat = ΔN / M(φ), Δlon = ΔE / (N(φ)·cos φ), on GRS80, with feet converted at the US survey foot. At parcel scale (a mile or less) this is accurate to well under a centimeter — the exported polygon drops cleanly into QGIS, JOSM, or the GeoJSON/WKT inspector tool. Remember the anchor's own accuracy governs: a phone-GPS anchor puts the whole parcel within phone-GPS accuracy of reality.

References

  1. Ghilani & Wolf, Elementary Surveying — traverse computation, closure, and precision standards.
  2. The deed or record map being walked — the governing description (and its basis-of-bearings note).