Grid to GroundLand Navigation Trainer
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Pine Creek

1:25,00010S FH

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Field guide

Learn
Use Show hint and on-screen tips.
Practice
Work on your own, then check each answer.
Take test
Build a test and get your score at the end.
Map controls & symbols
  • Move. Drag to pan. Pinch or use + and − to zoom. Use the fit button to reset the view or refocus on the terrain question.
  • Plot a point. Tap the map to plot or move your point. With the map focused, use arrow keys to position the cursor and Enter to plot.
  • Choose a map. Pick a 12 × 8 km training map by name and scale. Random maps switches after each drill or full course.
  • Read the grid. The main grid lines mark 1 km squares. In Learn, plotting and reading drills add 100 m and 10 m lines as you zoom. Practice and tests keep the 1 km grid.
  • Read the legend. Brown curves show contours, blue shows water, dashes mark trails, and diamonds mark reference points used in exercises. Use the scale bar to estimate distance.
Plot points & read coordinates

The Military Grid Reference System (MGRS) identifies locations with letters and numbers. Read right, then up: easting first, northing second. In 10S FH, 10S is the grid zone designation and FH identifies the 100 km square.

Plot 286 438. Start where lines 28 and 43 meet. Go 600 m right and 800 m up.
  • Choose 6-digit for 100 m squares or 8-digit for 10 m squares. The app allows an extra 10 m tap margin for eight-digit plots.
  • Plot a point. Tap within the given grid square and choose Check point. After checking, use See on map to inspect the correction.
  • Read coordinates. Use Zoom to A and enter the coordinates of the square containing A. Keep leading zeros.
  • In Learn, Grid aids opens the Grid tick guide. It divides a square into tenths.
Protractor
  1. Tap or drag Protractor onto the map. Drag the plate to move it, or tap Protractor again to close it. Drag the orange handle to turn it or tap the handle to straighten it.
  2. For grid coordinates, tap the orange handle to align the plate with grid north. The highlighted triangle automatically matches the map scale. Drag the highlighted triangle’s zero to the southwest corner of the 1 km square.
  3. Slide right until your easting tick meets the west grid line. Plot your point at the northing tick on the vertical edge.

Fit plate frames the protractor. Pan map moves the view while the plate stays put. Tap Move plate to grab it again. A tap inside a clear triangle plots a point; a tap on the plate does not.

Undo restores the last point, line, or tool adjustment. Your current practice question, notes, and tool positions save on this browser. Reopen a tool to resume its placement.

Keyboard: focus the map and use arrows, then Enter to plot a point. Use + / − to zoom. Focus a tool button and use arrows to move it; focus its orange handle to turn it. Ctrl / ⌘ Z undoes an adjustment outside text fields.

Azimuths & north references
  1. Place the protractor’s center (index) over A. Tap the orange handle to align its north line with grid north.
  2. Tap String below the map. Drag the blue handle toward B. The string continues past the handle to the edge of the map view. Read the black degree scale where the string crosses it. This is the grid azimuth from A to B.

An azimuth is an angle measured clockwise from a north reference. Grid north (GN) follows the vertical grid lines; magnetic north (MN) is the direction a compass points. The grid-magnetic (G-M) angle separates them. Red numbers on the protractor show back azimuths; the outer scale shows mils. A–B line connects the points when offered.

Grid to magnetic azimuth
Subtract an easterly G-M angle; add a westerly one.
Magnetic to grid azimuth
Add an easterly G-M angle; subtract a westerly one.
Back azimuth
The opposite direction, using the same north reference. Add 180° below 180°; otherwise subtract 180°.
Turns & mils
Add for right turns and subtract for left. A full circle is 360° or 6,400 mils.
Lensatic compass & pace count
  1. Open Lensatic compass. Drag the first tick (0) onto A. Drag the orange handle to rotate the graduated straightedge through B.
  2. The straightedge is graduated for 1:25,000: each small tick represents 100 m. Read at B; double that reading on a 1:50,000 map. For long or bent routes, add the straight sections.

Fit compass frames the tool. Edge only hides the case. Use Pan map to move the view and Move compass to adjust the tool.

Map scale
On a printed map, 1 cm is 250 m at 1:25,000 or 500 m at 1:50,000.
Paces to count
Meters ÷ 100 × paces per 100 m.
Personal pace count
Your count over 100 m on similar terrain. For a longer measured course: paces counted ÷ meters walked × 100. Keep the counting method consistent.
Walking time
Distance in km ÷ speed in km/h × 60 gives minutes.
Terrain association

Answer review. After checking an answer, use See on map. Numbered marks connect the ground view to the same terrain on the map.

Terrain association means matching terrain on the ground to features on the map.

Where are you? Note the facing direction above the ground view; directions follow grid north. Compare the hills and gaps with the map, then choose A, B, or C.

Zoom for detail. Crowded training maps show fewer contours from farther out. Zoom in for the fine lines; the map legend shows the spacing currently drawn.

Contour interval
The elevation difference between adjacent contour lines. Close lines indicate a steeper slope.
Hill
Closed loops rise toward the middle.
Ridge
Long crest with lower ground on both sides.
Draw
Low drainage with Vs pointing uphill.
Spur
Finger of high ground pointing downhill.
Saddle
Low gap between two peaks.
Depression
Low ground enclosed by contours with short inward marks (hachures).
Resection

Resection determines your position using two or more known points. The given magnetic azimuths run from your unknown position toward those points.

  1. Convert each magnetic azimuth to a grid azimuth using the G-M angle, then find its back azimuth. Use Grid back azimuth notes to keep the numbers handy.
  2. Drag the protractor’s center onto the known point and tap the orange handle to align with grid north. Tap String below the map and drag the blue handle to the grid back azimuth on the black degree scale.
  3. Tap Save line and repeat for each known point. Use Clear lines to start over.
  4. Plot where the lines cross. In modified resection, you are on a known linear feature, such as a road: plot where the single line crosses it. Tap Check position to see the correct lines.
Navigation course & mixed practice

Navigation course gives you five steps on one map. Plot the first checkpoint, preview and pick a route, walk a leg, then plot and walk to the final checkpoint.

Enter a magnetic azimuth and pace count. Walk leg shows where you stop. See course results reviews both legs.

Mixed practice rotates through grid coordinates, azimuths, terrain association, distance, and resection.

Calculator

Open Calculator from the map toolbar. Use the keypad or your keyboard, then press =. Clear starts a new calculation.

Learning path & tests

Learning path. In Learn mode, choose Start learning for six examples with three practice questions each.

Practice what I missed. After submitting a test, use this button for new coached questions about your missed skills. Your test results stay saved.

  1. Open Take test. Choose 1–100 questions, one or more topics, maps, and grid precision. Shuffle the questions or group them by topic.
  2. At the end, use Review answers to revisit questions by number. Blank answers count as missed.
  3. Tap Submit test for your score and explanations. To pause, open Test menu and choose Resume test to come back.
Open test setup
References

Independent map-work practice. Not military-endorsed or an official qualification; it does not replace field training.

NGA coordinate systems USGS map and compass guide Army TC 3-25.26 · Map Reading and Land Navigation (Army sign-in may be required) Army training task · Convert an Azimuth Lensatic compass reference