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10 coordinate-geometry calculators
Each one shows the whole computation — the intermediate values, the tables, and the checks — because an answer you cannot verify is an answer you cannot put on a plat.
Everything runs in your browser. Nothing you type is uploaded, stored or logged, and every calculator keeps working once the page has loaded, with or without a signal.
- Traverse closure and compass-rule adjustmentEnter a closed traverse as bearings or azimuths and distances and get latitudes, departures, misclosure, the 1:X precision ratio, a compass-rule or transit-rule adjustment, and adjusted coordinates.
- Horizontal curve solverSolve a simple circular curve from any two of R, Δ, T, L, C, M and E, with degree of curve by both the arc and chord definitions, curve stationing, and a deflection-angle staking table.
- Vertical curve solverEqual-tangent parabolic vertical curves: BVC and EVC stations and elevations, the high or low point, K value, external offset, and a grade-elevation table at full stations.
- Bearing and azimuth converterConvert quadrant bearings to azimuths and back, get the back bearing and back azimuth, and add or subtract angles in degrees-minutes-seconds.
- Area by coordinatesCompute a parcel's area from its coordinates by the shoelace method, cross-checked against a double-meridian-distance computation sheet, reported in square feet, acres, square meters and hectares.
- Inverse and forward COGOInverse between two points for distance, azimuth and bearing, or compute forward from a point along a bearing and distance. Includes slope reduction and the direction-direction and distance-distance intersections.
- Latitude and departure calculatorBreak any course into its latitude and departure, or rebuild a course from its components — with the sign conventions spelled out and a running total for a whole set of courses.
- Stationing calculatorStation arithmetic in US or metric form: add and subtract distances, find the distance between two stations, apply a station equation, and list the full stations across a range.
- Scale factor and unit conversionGrid scale factor, elevation factor and combined factor for ground-to-grid conversion, plus exact conversions between US survey feet, international feet, meters, chains, links and rods.
- DMS and decimal degrees converterConvert degrees-minutes-seconds to decimal degrees and back, in every format a surveyor types them, with radians, grads and arc seconds alongside.
A note on the units
Two feet have been in legal use in the United States: the international foot, exactly 0.3048 m, and the US survey foot, exactly 1200/3937 m. They differ by two parts per million — nothing on a tape length, four feet on a State Plane northing of two million. The calculators here never use an ambiguous “feet”; every conversion names which foot it means.