Sokuten: Survey Calculator

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. After an import you see how many points, parcels, duplicate names and unreadable lines came in, and the plot draws each parcel with its area (coordinate method). Tap two points to see the distance and bearing. 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. The app itself connects only to the App Store (for purchases, restores and the like); your data is never sent to our servers. ■ No subscription All calculations, the plot and SIMA import are free. From version 1.2, points brought in from SIMA files or CSV paste do not count toward the 50 free points — points you enter by hand or register from a calculation count; SIMA and CSV imports and the bundled sample do not. Sokuten Pro (one-time purchase — see the App Store listing for current pricing) unlocks unlimited new points, SIMA/CSV export, bulk copy of all points, and unlimited history (the free version shows the last 7 days of history). Note: Verify results before relying on them. For public survey or registration deliverables, follow the Survey Act and your client's specifications.