Convert Bearing and Distance to Coordinates on Your Phone

When you can see it but can't walk to it

A target, a landmark, a casualty on the far side of a ravine. You've got a compass bearing and a rough distance estimate. A polar plot is just turning those two numbers into a grid you can report or come back to later.

Doing this on paper takes a protractor, a map and a careful hand, maybe five minutes if nothing goes wrong. FieldGrid does the same thing from your GPS fix in a few seconds, no protractor required.

How to project a waypoint in FieldGrid

On the Map tab, wait for a good GPS fix, then press and hold WP+.
Choose By distance and bearing…. The Offset waypoint sheet opens and shows your own MGRS as the starting point.
Type the Distance and pick m or km.
Type the Bearing (true) and pick degrees (0-360) or mils (0-6400). The footer shows the other unit.
Check the grid and lat/long under Resulting point, give it a Name and Category, and tap Save.

A few numbers to see it work

Starting at 11SKB 7205 8108 (37.74870, -119.58720)
Distance	Bearing	Footer	Resulting point
850 m	1200 mils	≈ 67.5° true · 1200 mils	11SKB 7285 8138 · 37.75162°, -119.57827°
400 m	4800 mils	≈ 270.0° true · 4800 mils	11SKB 7165 8109 · 37.74870°, -119.59175°
1.5 km	300 mils	≈ 16.9° true · 300 mils	11SKB 7253 8250 · 37.76161°, -119.58225°

Row one: easting climbs from 7205 to 7285, northing from 8108 to 8138. Each unit is 10 m, so that's 800 m east and 300 m north, about 854 m in a straight line. Close enough to the 850 m you typed, give or take the squares' own rounding.

True, magnetic, grid: pick the right one

FieldGrid wants a true bearing, measured off true north. A magnetic compass hands you a magnetic bearing, a paper map hands you a grid bearing. Where the gap between them runs a few degrees, a kilometre out that's tens of metres off to the side, which is the difference between finding the clearing and finding the tree line next to it.

Bearing came off a lensatic compass? Correct it to true with the declination printed on your map margin before you type it in. The app's own compass already reads true heading, so a bearing straight off that one needs no conversion at all.

A sanity check before you trust it

Once saved, the Waypoints list shows the distance and true bearing from where you're standing to the new point. Stand still and those numbers should roughly match what you typed; if they don't, you picked the wrong unit somewhere.

Where this goes sideways

Mils versus degrees: type 1200 as degrees and it gets rejected outright since degrees stop at 360; type 120 as mils and you get a wildly different direction from 120°. Check the footer line before you save.
The start point is always your live GPS fix, never another waypoint, so you have to be standing where you're measuring from.
A comma works fine as a decimal point too: 1,5 km reads as 1.5 km.
Every projected point burns a waypoint slot. Free gives you 5, plus one per short rewarded ad; Pro has no ceiling.

Questions and answers

How accurate is a projected point?

Only as good as your GPS fix, your distance estimate and your bearing, in that order of blame. A 5% distance error at 1 km costs you 50 m; a 2° bearing error at the same range is roughly 35 m to the side. The app's own maths adds nothing worth worrying about.

Can I enter the bearing in mils?

Yes, switch the bearing unit to mils and type 0-6400 NATO mils; the footer shows you the degrees equivalent so you can double-check.

Can I measure distance and bearing between two waypoints?

Not directly. FieldGrid only shows distance and bearing from wherever you currently are to each waypoint, never between two saved points.

Does this work offline?

Yes. The projection is calculated on the phone from your GPS position.

Compass app with mils: read a bearing in degrees and NATO mils · FieldGrid

How to convert bearing and distance to coordinates (a polar plot on your phone)