Survey Traverse Lab
Accumulate east and north coordinates from a control point using each leg's planar distance and absolute azimuth. The difference between the computed and expected endpoint is the closing error. Bowditch apportions it by leg length; the transit rule uses each axis's absolute observed component. Compare raw and adjusted station paths without treating the result as certified field survey evidence.
Key features
- Absolute azimuths measured north clockwise or east counterclockwise
- Explicit degrees [0,360) or gon [0,400) angle units
- Raw accumulated stations, east/north closure vector, linear error and 1:N precision ratio
- Side-length Bowditch and axis-component transit corrections compared
- Explicit unavailability when a transit axis has no observed component
- Local SVG path, all-station CSV and assumptions/corrections JSON downloads
How to use
- Enter start and expected endpoint E/N metre coordinates in one planar grid. For a closed loop, make them equal.
- Choose bearing basis and angle unit, then enter one distance (m), absolute azimuth per line. The example is a four-leg square.
- Calculate the raw endpoint, east/north closure vector, misclosure distance and 1:N ratio.
- Compare Bowditch and transit station paths in the SVG and table, then export CSV or JSON.
Use cases
- Learn the closure arithmetic behind field observation tables
- Compare degree versus gon and north versus east bearing conventions
- Examine how Bowditch and transit corrections change stations
- Numerically check a planar traverse between known start and endpoint
Frequently asked questions
Which direction is azimuth zero?
With north clockwise, 0° is north and 90° east. With east counterclockwise, 0° is east and 90° north. A circle is 400 gon and 100 gon is a right angle. Each input is an absolute direction, not a turn angle.
How do Bowditch and transit differ?
Bowditch distributes the negative east and north closure errors in proportion to each leg's length over total length. Transit weights east correction by absolute observed east change and north correction by absolute north change. If an axis has no observed component but needs correction, transit is unavailable.
How is linear precision 1:N computed?
N is total observed length divided by the unadjusted endpoint misclosure distance. A nearly zero computed closure is labelled within floating precision, not infinitely accurate. A fitted adjusted endpoint is a property of the correction formula, not proof of survey accuracy.
Can I paste latitude/longitude or EPSG coordinates?
Do not treat latitude and longitude degrees as metre distances. All E/N coordinates and distances here must be in the same local planar metre grid. The tool infers no CRS, datum, projection scale, elevation correction or magnetic declination.
Can this certify a land boundary survey?
No. It does not inspect observation quality, redundancy, angular closure, instrument corrections, legal tolerances or control-point accuracy. It is an educational numerical check, not a certified survey result.
Privacy
Distances, azimuths and coordinates are calculated in this browser tab. Downloads are created locally on request; observations are not uploaded to a server.
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