Gridwalk: Pace & Resection

Say the grid. Know your pace. Fix where you are.

Gridwalk does the map-and-compass arithmetic of land navigation, one screen for each job. There is no map to load and nothing to sign up for.

CONVERT ANY GRID

Type an MGRS, UTM or latitude/longitude (decimal degrees, degrees and minutes, or degrees, minutes and seconds) and read the others at once. Pick the precision from 10 km down to 1 m and see the square it names. Gridwalk says it the way you read it off a map: right, then up. WGS84 and NAD83 (the same to a metre or two) plus ED50 for European maps. Tap My position to fill in where you are; if you would rather not share it, type the grid.

COUNT YOUR PACE IN BEADS

Walk a measured course once and Gridwalk keeps your pace per 100 metres for flat, uphill and downhill, plus two terrains you name. Then walk: tap each pace and the bead strip slides, four 1 km beads and nine 100 m beads, the way the pace beads on your pack do. Change terrain mid-leg and it keeps the sum. Count every step or one foot only, your choice, and the screen says which.

FIX WHERE YOU ARE

Take two or three bearings on landmarks you can find on the map with your own compass and type them in. Gridwalk turns magnetic into grid, draws the rays back from the landmarks and gives you the fix. With three bearings it shows the triangle and tells you whether it is a good fix or whether to pick a landmark at a different angle. The same screen does intersection, to locate a distant point from two places you know, and modified resection along a road or a stream.

PLAN EVERY LEG

Enter the points of your course. For each leg you get the grid azimuth, the magnetic azimuth to set on your compass, the back azimuth, the distance, and the paces and beads for your terrain, in degrees or mils. Or start from a point, an azimuth and a distance and get the new grid.

MAGNETIC AND GRID, WITHOUT THE SIGN MISTAKES

Type the grid-magnetic angle printed in your map's margin, or let Gridwalk look up the declination for today's date with the World Magnetic Model 2025 (built in, valid to the end of 2029, no signal needed). The results say in words what to add or subtract. The map's printed value always wins.

MAP SCALE, WITHOUT THE CALCULATOR

Measure in millimetres on a 1:25,000, 1:50,000, 1:100,000 or your own scale and read metres, beads and paces. See how wide a grid square is on paper. Convert degrees, mils and grads.

BUILT FOR THE FIELD

Big targets for gloved hands. Day, night and red modes that keep your night vision. Works in portrait and landscape on iPhone and iPad. In English.

FOR

Cadets and soldiers learning land navigation, search-and-rescue volunteers, hunters, hikers and orienteers, geocachers.

PLEASE NOTE

Gridwalk is a calculator, not a navigator. Carry a map and a compass. Your phone's position is only as good as its view of the sky, iPads without GPS cannot give a position, and many land navigation courses and tests do not allow phones. Gridwalk is not affiliated with or endorsed by any military or government body.

Your points, pace counts and courses stay on your phone.