# Sokuten: Survey Calculator — SIMA import & field calcs

> SIMA import & field calcs (iPhone/iPad app by Yuya Tanaka.)

- Source: https://appshunter.io/ios/app/sokuten-survey-calculator/id6790451185 (this page in markdown: same URL + `.md`)
- Developer: [Yuya Tanaka](https://appshunter.io/developer/1895106450)
- Category: Productivity, Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 3 MB
- Languages: American English, Japanese
- Released: 2026-07-20
- Data updated: 2026-08-27
- User reviews in markdown: https://appshunter.io/ios/app/sokuten-survey-calculator/id6790451185/reviews.md

## What is Sokuten?

Read SIMA files, compute coordinates on site, and write them back — entirely on your iPhone. A coordinate calculator built for field surveying in Japan.

■ SIMA (survey data exchange format) support
Import SIMA files received via AirDrop or the Files app. Unreadable lines never stop the import: a report tells you which lines were skipped and why, and unrecognized records are preserved verbatim and written back in place on export.

■ Seven field calculations
Inverse (distance, bearing, height difference), radiation, open/closed traverse with closure error and compass-rule adjustment, intersection, area (coordinate method), offset stakes, and perpendicular foot. Register any result as a new point with one tap.

■ Input built for the field
A large keypad, one-tap switching between DD.MMSS and decimal degrees, intuitive negative coordinates, and high-contrast display for outdoor readability.

■ Designed so data survives
Atomic saves with three generations of automatic backups. If a save ever fails you are told immediately and can retry. No network access; your data is never sent to our servers.

■ No subscription
All calculations and SIMA import (up to 50 points) are free to try. Sokuten Pro (one-time purchase — see the App Store listing for current pricing) unlocks unlimited points, SIMA/CSV export, and unlimited history.

Note: Verify results before relying on them. For public survey or registration deliverables, follow the Survey Act and your client's specifications.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Sokuten Pro | $19.99 | one-time |



## Version history (last 5 releases)

### 1.1.2 — 2026-08-17

Minor internal update. No functional changes.

### 1.1.1 — 2026-08-14

Updated store listing information. No functional changes to the app.

### 1.1.0 — 2026-08-10

We refreshed the app icon with a crosshair motif so the app is recognizable at a glance. We also reordered the app name to make it easier to find.

### 1.0.2 — 2026-07-31

You can now see update information in the app. New features and important changes will be shown the first time you open each updated version.

### 1.0.1 — 2026-07-29

At a natural milestone, the app may now ask once for an App Store review. Nothing else has changed.

## More apps by Yuya Tanaka

- [Dovio](https://appshunter.io/ios/app/dovio/id6762978468)
- [Foghorn: ADHD Routine Alarms](https://appshunter.io/ios/app/foghorn-adhd-routine-alarms/id6788937334)
- [Inlet: AI Anxiety Journal](https://appshunter.io/ios/app/inlet-ai-anxiety-journal/id6789019421)
- [Shiodoki: Japan Tide Charts](https://appshunter.io/ios/app/shiodoki-japan-tide-charts/id6789547788)
- [Dencho: Tape Calculator](https://appshunter.io/ios/app/dencho-tape-calculator/id6789548710)
- [TenthFrame: Bowling Scores](https://appshunter.io/ios/app/tenthframe-bowling-scores/id6789774323)

All apps by Yuya Tanaka: https://appshunter.io/developer/1895106450

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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 2026-08-27.*