# COGO Survey Calculator — Traverse, closure & CAD export

> Traverse, closure & CAD export (iPhone/iPad app by Gabriel John Fordan.)

- Source: https://appshunter.io/ios/app/cogo-survey-calculator/id6777398516 (this page in markdown: same URL + `.md`)
- Developer: [Gabriel John Fordan](https://appshunter.io/developer/6777398518)
- Category: Productivity, Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 26.0 · 7 MB
- Languages: American English
- Released: 2026-06-10
- Data updated: 2026-07-20
- User reviews in markdown: https://appshunter.io/ios/app/cogo-survey-calculator/id6777398516/reviews.md

## What is COGO Survey Calculator?

Native COGO calculator for surveyors and field crews — traverse, closure, curves, intersections, area, and CAD export. Fully offline.

WHAT YOU CAN DO
• Compute a bearing-and-distance traverse with running coordinates
• Inverse / join: two points to distance, azimuth, and quadrant bearing
• Inverse list / radiations: bearing & distance from one occupied point to every other point at once
• Sideshot reduction: horizontal angle, zenith angle, and slope distance from an occupied station to northing, easting, and elevation
• Closure: linear misclosure, misclosure bearing, and precision ratio (1 : N)
• Balance a traverse by the Compass (Bowditch) or Transit rule
• Enclosed area by coordinates, with acres / hectares and perimeter
• Horizontal curve solver — R, Δ, arc, tangent, chord, external, mid-ordinate, degree of curve, PC & PT — plus deflection-angle / chord stakeout, exportable as CSV
• 3-point circle / arc — fit a circle through three points and divide the arc into equally spaced stake points
• Angle calculator — add/subtract angles, compute the angle between two bearings, add/subtract an angle from a bearing, and keep an editable running total
• POB calculator — chain editable bearing-distance calls from a point of beginning and read every running coordinate
• COGO intersections — bearing-bearing, bearing-distance, distance-distance — and 3-point (Tienstra) resection
• UTM converter — enter latitude/longitude as decimal degrees, DMS with N/S/E/W, compact DDMMSS, or packed D.MS
• State Plane Coordinates (SPCS83) — lat/lon to State Plane on GRS80/NAD83, with scale factor, convergence, and combined grid-to-ground factor
• Grid ↔ Ground converter — convert distances through a combined scale factor, typed directly or derived from a State Plane zone and position
• Horizontal alignment / roading — PI-chained tangents, circular curves, optional spirals, stationing, station & offset, and stakeout
• Predetermined / hinged area subdivision — solve a missing bearing/distance, a parallel cutoff, or a hinged line to hit a target parcel area
• Metes-and-bounds legal description — generate a written deed description from a closed traverse
• Plot / sketch view of the traverse with north arrow, scale bar, and legend
• Import and export points as CSV in your choice of column layout (PNEZD, PENZD, NEZ, ENZ …) and delimiter
• Export DXF (AutoCAD R12) for CAD / GIS and a single-page PDF report — CSV, DXF, and PDF export are free for everyone
• Work in DMS, decimal degrees, or packed DDD.MMSS / D.MS (CAD and Topcon-style); azimuth or quadrant bearing; feet or meters
• Use the native iOS number keyboard by default, or switch to the in-app survey keypad when you want dedicated DMS keys
• Ask “Theo,” the on-device AI assistant (Apple Intelligence), in plain English

PRIVATE BY DESIGN
100% offline. No account, no network, no ads, no tracking. Your jobs and points never leave your device.

WHO IT'S FOR
Land surveyors, party chiefs, survey techs, civil engineers, and students.

FREE & PRO
Free includes one job and up to ten points, full on-screen computation, and CSV / DXF / PDF export. COGO Pro unlocks unlimited jobs and points, Compass/Transit closure adjustment, and enclosed-area output — as a Weekly, Monthly, or Yearly subscription, or a one-time Lifetime purchase.

Always verify computed results against your project control. This app is a field calculator, not a substitute for a licensed surveyor's checks.

SUBSCRIPTION DETAILS
COGO Pro Weekly, Monthly, and Yearly are auto-renewable subscriptions; Lifetime is a one-time purchase. Payment is charged to your Apple Account at confirmation. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period; manage or cancel anytime in Settings.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://cogo.vendrato.com/privacy

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| COGO Pro Monthly | $1.99 | per month |
| COGO Pro Yearly | $11.99 | per year |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| COGO Pro Lifetime | $29.99 | one-time |



## Version history (last 5 releases)

### 2.0 — 2026-07-07

v2.0 includes the v1.95 field-entry tools plus the new keyboard and Pro pricing update.

• Angle between bearings: compute the included angle and both clockwise turn directions.
• Bearing ± angle: start from a bearing, add or subtract an angle, and read the resulting quadrant bearing, azimuth, and packed D.MS value.
• POB calculator: chain editable bearing-distance calls from a starting coordinate and see each running coordinate plus the final inverse.
• Editable angle tape: manually correct any previous running-total entry and the total recomputes immediately.
• UTM DMS input: enter CSRS-PPP-style latitude/longitude directly as DMS, DDMMSS, packed D.MS, or decimal degrees.
• Faster bearing entry: packed D.MS is now the default, and short DMS entry no longer needs leading zeroes.
• Input preference: native iOS number keyboard is the default, with the in-app survey keypad still available for dedicated DMS keys.
• COGO Pro pricing now supports Weekly, Monthly, Yearly, and Lifetime options.

Fully offline. Thanks for using COGO Survey Calculator.

### 1.9 — 2026-07-04

v1.9 — built around feedback from a surveying student.

• Angle-right traverse entry: occupy a point, pick a backsight, type the angle turned right — the leg's azimuth and quadrant bearing preview live, just like your total station measures.
• Bearing ↔ azimuth converter in the Angle Calculator: enter either form and read every representation — azimuth (DMS and decimal), quadrant bearing, and packed DDD.MMSS.
• Every State Plane zone: all 123 SPCS83 zones, plus a preview of the new SPCS2022 (NATRF2022) system — 673 zones from NGS's finalized parameters, each verified against an NGS computation — behind a searchable, state-grouped picker.
• Vertical curve profile table: elevations and grades from PVC to PVT at your staking interval, exportable as CSV.
• Smoother entry: DMS bearings auto-advance (083 → degrees, then minutes, then seconds — no separator keys), the active keypad field is highlighted, and traverse legs can now be deleted to fix a mis-entry.

Fully offline. Thanks for using COGO Survey Calculator!

### 1.8 — 2026-07-02

v1.8 — three new field tools and a big accuracy pass.

• Curve stakeout table: deflection angles and chords from the PC at your staking interval — snap to even stations, get coordinates when you give the PC and its tangent azimuth, and export the table as CSV.
• Grid ↔ Ground converter: reduce distances through the combined scale factor — type the CSF directly or derive it from any State Plane zone, latitude/longitude, and ellipsoid height.
• Sideshot reduction: turn an occupied point, orientation, horizontal angle, zenith angle, and slope distance (with instrument/target heights) into a point's northing, easting, and elevation — then save it to the job.
• State Plane grid coordinates now support the US survey foot explicitly (choose US survey feet, international feet, or meters).
• 3-point resection accepts an optional third angle to catch a station outside the control triangle.
• European decimal commas, grouped numbers, and non-UTF-8 files now import safely, and the level book, PDF report, and plot all match the Results screen exactly.

Fully offline. Thanks for using COGO Survey Calculator!

### 1.7 — 2026-06-22

v1.7 — Digital Level Book.

• New Digital Level Book: reduce a differential-leveling run straight from your field notes. Enter a starting elevation and your backsight / intermediate / foresight readings to get the height of instrument and reduced level at every station, the ΣBS − ΣFS arithmetic check, loop misclosure against a closing benchmark, and an optional misclosure distribution — then export the reduced sheet as CSV.
• Reliability fixes: a new traverse on an empty job now anchors its start point correctly, and editing legs no longer disturbs the traverse order, so coordinates, closure, and area stay consistent across every tab.
• More fixes: the assistant now reports the correct area for jobs with curved boundaries, plus corrections to DXF export, the horizontal curve solver, alignment spirals, the angle calculator, and area subdivision.

Fully offline. Thanks for using COGO Survey Calculator!

### 1.6 — 2026-06-20

v1.6 — Link (connecting) traverses.

• A traverse no longer has to close back on the point it started from. On the Closure & Area screen, switch the traverse type to Link and choose a separate known closing point — pick one of the job's stored points or type its published northing/easting.
• Misclosure, precision ratio, and Compass/Transit balancing are measured against that closing point, so you can tie into a second control point instead of looping back. The chosen closing point is saved with the job and carried into the PDF report and Theo's closure answer.

Fully offline. Thanks for using COGO Survey Calculator!

## More apps by Gabriel John Fordan

- [TrueCut: Construction Calc](https://appshunter.io/ios/app/truecut-construction-calc/id6780490646)

All apps by Gabriel John Fordan: https://appshunter.io/developer/6777398518

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-20.*