CoordKit
A field-grade coordinate instrument — six formats, offline measurement and a stamped camera, built around a map you aim rather than poke.
The Challenge
Every coordinate app puts a pin under your thumb. You tap, the finger covers the number you came to read, and the fix you get is wherever your fingertip landed — not where you meant. Worse, the moment a surveyor, a driller or a pilot needs MGRS, a stamped photo or an area measurement, the consumer apps stop and the professional ones start at a subscription price with a training course attached. CoordKit had to be precise enough to trust in the field and simple enough to open once, in the rain, with one hand.
The Solution
- ✦A fixed reticle: The map moves under a crosshair that never moves. You aim instead of poking, so the coordinate is continuous and nothing covers the readout.
- ✦Modes, not routes: Position, Convert, Measure, Compass and Speed swap one panel's contents while the map and the framed point stay put — no navigation between tools.
- ✦Honest precision: The app prints only the decimal places the device's reported accuracy justifies, and names which source an elevation came from.
- ✦Evidence you can file: A camera that stamps coordinates, elevation and time into the image and its EXIF, plus GPX, KML and CSV export.
Tech Stack
The map is a picker; the readout is the product
Most mapping apps treat the map as the answer. CoordKit treats it as an input device. The camera has bottom padding equal to the panel height, so the camera's own centre is the crosshair's point — there is no offset arithmetic anywhere in the codebase, and a pan is a continuous edit of the coordinate rather than a discrete guess.
That one decision cascades. Because the point is framed rather than tapped, the readout can live permanently at the bottom of the screen without ever being obscured. Because the readout is permanent, the tools can be modes of that panel instead of separate screens — Position, Convert, Measure, Compass and Speed swap its contents while the map, the framed point and the coordinate stay exactly where they were.
Precision you can argue with
A consumer GPS receiver will happily hand you eight decimal places of latitude while being twelve metres wrong. CoordKit refuses to print digits the fix does not support: the number of decimals shown is derived from the accuracy figure the device reports, so the readout degrades visibly when the sky closes in.
Elevation follows the same rule. The app prefers a public terrain dataset, falls back to the device's own altimeter, and tells you which one it used — because a barometric altitude and a surveyed height are different claims about the world.
What shipped
Six coordinate formats — decimal degrees, DMS, DD N/S/E/W, UTM, MGRS and Plus Codes — with smart detection on input, so pasting anything recognisable works. Distance and area measurement on a spherical model. A compass that flags magnetic interference instead of quietly pointing the wrong way. Speed with trip distance and a moving average. A camera that burns coordinates, elevation and time into the photo and its EXIF metadata, for when a screenshot is not evidence. Saved points with GPX, KML and CSV in both directions.
No advertising, at all. The ad SDK was removed outright rather than configured off — a linked ad framework still ships a sample app id in both manifests and still forces a tracking permission string for a prompt the app never shows. Pro is the only revenue.
Interface Design
Visual High-Fidelity
Aim, don't poke
Fixed reticle over a moving map · six coordinate formats at once
Convert and keep
Smart-detect any input format · saved points with GPX, KML and CSV export
Instruments for the field
Interference-aware compass · speed, trip and moving average
Proof of where you stood
Coordinate-stamped camera with EXIF · accuracy you can defend