What you get

Every photo, self-describing

The stamp is part of the image, so it survives being emailed, resized, screenshotted and stripped of its EXIF. The app also keeps its own record of every measurement, at full precision, in case the photo doesn't make it.

The captures library, showing stamped photographs grouped by day — Every capture, grouped by day

Capture detail showing all four coordinate formats, both altitudes and both bearings — All four formats, both datums, both norths

Stamp settings with a live preview of the plate that will be burned in — Live preview before it is burned in

Export screen offering a PDF contact sheet and a full-precision CSV — PDF contact sheet or full-precision CSV

Built for the grid

Correct conversions, stated accuracy

The things that are easy to get subtly wrong, done properly — and labelled, so nothing on the stamp has to be guessed at later.

MGRS · UTM · DD · DMS

Four formats, one tap apart

Cycle the readout to whichever grid you actually work in. MGRS precision is yours to set, and a position outside the grid says so rather than inventing a reference.

MSL / HAE

Altitude in both datums

Height above sea level and above the ellipsoid, each labelled. They can differ by tens of metres, and a stamp that shows one without saying which is a stamp that gets misread.

TRUE / GRID

Bearing in both norths

True north and grid north, with the grid convergence applied. Held more than 45° off level, the bearing is marked as tilted instead of quietly trusted.

± METRES

The accuracy is never hidden

The horizontal accuracy of the fix sits on the readout and on the photo, always, in metres. You can see whether a shot is worth taking before you take it.

SIMULATED

A spoofed location is flagged

If the position is being simulated by software, the stamp says so — and that warning cannot be switched off, in settings or anywhere else.

PDF · CSV

Export that isn't held hostage

A PDF contact sheet with photograph and measurements side by side, or CSV with the unrounded values for a spreadsheet or a GIS import. Never watermarked, never metered.

Plainly

What it is, and what it isn't

A tool you're going to rely on should tell you where its limits are before you find them yourself.

It is a phone, and it says so.A phone's GNSS is good to a few metres, not to a centimetre. FieldProof's job is to convert that position correctly and to state the accuracy honestly on every photo — not to pretend it is something it isn't.
The record survives the photo.Measurements are indexed in the app at full precision. If the photo library refuses the write, the image and the record are both kept anyway, and the app tells you it happened.
Your photos and coordinates stay on your device.No account, no server, no sync. Location is used only while you're in the app, and neither your position nor your photographs are ever transmitted anywhere.
Both orientations, gloves on.Landscape and portrait, with the stamp upright in all four. Tap targets are oversized on purpose, and the readout uses monospaced figures so the digits don't jitter as the fix settles.

Pricing

$12.99

One-time purchase. No subscription.

The camera, every coordinate format and the whole stamp are free — MGRS, UTM and lat-lon, altitude in both datums, bearing in true and grid north. The one-time unlock is for getting the work back out: PDF and CSV export, covering everything you've already shot, plus a project per site and your company name on the stamp. Buy it once and it stays unlocked on every device signed in to your Apple Account.

No ads. No account. Your photos and coordinates never leave the device.