Grade is off: too deep, too shallow or the numbers look wrong

You weren't on the survey route Most likely

The target always comes from the nearest point on the route. Park beside the route on higher ground, and the target is the ditch bottom over there. The blade digs in to reach it.

Check:

1. Look at the map, left of the tall white guide column. Your machine is the pink arrow. The survey route is the dotted orange line.
2. The tip of the arrow should sit on the dotted line. If it is off to one side, this is your cause.

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More than about 100 ft (30 m) off the route, an orange banner across the top of the map also says how far: … from survey line — accuracy may decrease. Closer than that there is no banner, so look at the arrow.

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Fix:

1. Keep the blade up.
2. Drive onto the route until the tip of the pink arrow sits on the dotted orange line.
3. Line the machine up to drive along the route.
4. Lower the cutting edge to the ground.
5. Tap Resume (if you tapped Hold) or Start (if you tapped Stop).

You calibrated after you surveyed

Your survey was recorded with the calibration you had while surveying. Calibrating to a benchmark afterwards changes today's numbers, but not the survey's. If the benchmark was set on another day (another base setup), the two no longer line up. The same happens if you typed a new Benchmark Offset in Settings.

Check:

1. Tap the BM badge in the row of badges at the top of the map, just left of the wrench button. The Calibrate Elevation window opens.
2. Read the line under the title. Calibrated to … ends with how long ago. A time after you saved the survey means you calibrated after surveying.

Fix: calibrate to the survey itself, so today's numbers match it again.

1. Drive onto the route, to a spot you haven't cut yet.
2. Lower the cutting edge onto the ground.
3. Tap the BM badge. The Calibrate Elevation window opens.
4. Find the Loaded design row, near the bottom of the window (Loaded survey if you only have a survey loaded).
5. Tap Surveyed ground in that row, if it isn't already picked.
6. Tap Calibrate, the button at the right end of that row.
7. Keep the machine still for 5 seconds while the app averages.

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You should see the line under the title turn green: Calibrated to design point · just now (or survey point). Tap Close, then Start again on the route. Next time, calibrate before you survey, not after. More: Benchmarks and calibration.

The base moved, or it's another day, and you didn't calibrate

You moved the base or set it up again, or you came back the next day, and started on yesterday's survey or design without calibrating. Today's GPS elevations are shifted from yesterday's, the same amount everywhere. Shifted up, the blade dives.

Check:

1. Tap the BM badge. The Calibrate Elevation window opens.
2. Read the line under the title. Restored from … — recalibrate before working or Not calibrated — elevations are raw GPS means you haven't calibrated today.

Did a Calibrate GPS? window come up when you opened the job or the design, and you tapped Skip? That's this cause too.

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Fix: calibrate on the field's benchmark before you tap Start.

1. Drive to the benchmark and park on it.
2. Lower the cutting edge onto it.
3. Tap the BM badge.
4. Tap your benchmark under CALIBRATE TO. A card shows how far away you are.
5. Tap the orange Calibrate to … (5s avg) button on the card. Keep still for 5 seconds. Pictures for every tap: Calibrate on the benchmark.

No benchmark? Calibrate to the loaded survey or design instead, on ground you haven't cut (Surveyed ground steps above). On a stretch already cut to grade, use Design grade instead (how). Picking up a saved job: Resume a job shows where the Calibrate GPS? window comes in.

Blade height was wrong while you surveyed

The app takes the blade height off every survey point as it records. A blade height bigger than the real one, or an implement carried lower than its transport position while surveying, records the ground too low. The design follows it down, and so does the blade.

Check: Was Blade Height (SURVEY box of Settings) set for this implement when you surveyed? Was the implement raised all the way the whole survey? Look for an orange Blade Ht 0 — antenna level chip on the survey map too (that one makes the design sit too high).

Changing Blade Height now doesn't move a survey you've already recorded. It only changes the next survey.

Fix: calibrate to the survey on ground you haven't cut (Surveyed ground steps above). That takes out an error that is the same all along the route. Or set the right blade height and survey again. More: Set blade height.

The benchmark is wrong or from another day Most likely

Check:

1. Tap the BM badge at the top of the screen, just right of the GPS badge. The Calibrate Elevation window opens.
2. Read the line under the title. Not calibrated — elevations are raw GPS or Restored from … — recalibrate before working means you haven't calibrated today.

Fix: calibrate on your benchmark.

1. Drive to the benchmark and park on it.
2. Lower the cutting edge onto the ground.
3. In the Calibrate Elevation window, tap your benchmark under CALIBRATE TO. A card shows how far away you are.
4. Within about 3 m (10 ft) the button on the card reads Calibrate to followed by the benchmark's name and (5s avg). Tap it.
5. Keep the machine still for 5 seconds while the app averages.

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Farther than about 3 m, the button reads Calibrate Anyway (5s avg) and asks you to confirm, because it would give the spot where you are the benchmark's elevation. Tap Cancel and drive closer.

No benchmark? Use the loaded survey or design instead: park on an undisturbed point of the route (ground you haven't cut), lower the cutting edge, and tap Calibrate on the Loaded design (or loaded survey) row, with Surveyed ground picked. Never calibrate on ground you've already cut. More: Benchmarks and calibration.

The RTK base moved, was replaced or restarted

Check: Was the base set up somewhere else, knocked, or swapped since the survey? A base that averages a new position each time it starts counts as moved.

Fix: Recalibrate to a saved benchmark before grading (steps above). Do it every time the base is set up.

You calibrated with the implement raised

Check: The error matches roughly how high the cutting edge was off the ground.

Fix: Lower the cutting edge onto the ground and calibrate again.

The calibration came with you from another field

Check: The calibration stays through mode changes and restarts. Did you switch fields or workflows?

Fix: Recalibrate where you are now.

Blade Height is wrong Most likely

Check:

1. Tap Settings, the fourth button down the right-hand column.
2. Scroll down to the SURVEY box, about a third of the way down (how to scroll).
3. Read Blade Height, the second row. It's how far the cutting edge sits above the ground with the implement raised in transport (survey) position. It is not the antenna height. The app subtracts it from every survey point.

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Fix with Auto Measure (needs the app connected to your kit and a green RTK):

1. Park on level ground.
2. Tap Auto Measure, right of the Blade Height box. The Auto Measure Blade Height window opens at Step 1: Transport Position.
3. Raise the implement all the way up.
4. Tap Measure UP Position. Keep still for 10 seconds.
5. At Step 2: Ground Position, lower the implement onto the ground.
6. Tap Measure DOWN Position. Keep still for 10 seconds. The difference is the blade height.

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A survey already recorded with the wrong blade height is off by the error everywhere. Survey again, or calibrate to that survey with the blade on the ground at a known point. More: Set blade height.

You carried the implement at a different height while surveying

Check: Was the implement raised more, or less, than when you measured blade height?

Fix: Survey with the implement raised all the way every time.

Blade tilt changed between survey and grading

Fix: Keep the tilt the same from survey through grading.

Auto Measure gave a doubtful value

Check: The result said Measurement Uncertain: the GPS moved more than an inch during a measurement.

Fix: Tap Retry Measurement with the machine dead still on RTK Fixed. Or, if you've measured the height with a tape, type it in the Blade Height box instead.

You're too far from the survey or design Most likely

Check: The survey row says Too far from route — move closer (more than 50 m away), or the design-grade calibration says Too far from the design line — move onto the run first.

Fix:

1. Drive onto the run.
2. Lower the implement onto the ground.
3. Tap Calibrate on the row again.

You're not at the benchmark

Check: Tapping a benchmark more than 3 m away gives Calibrate Anyway (5s avg), which warns that it gives your current spot the benchmark's elevation. In Field Survey you see You are … from “…”. Drive within 10 m to calibrate.

Fix:

1. Tap Cancel.
2. Drive onto the benchmark. The card counts down the distance.
3. Lower the implement and calibrate (steps).

No RTK Fixed during the 5-second average

Check: The app says No RTK samples collected. Check GPS fix., or the row says Waiting for GPS fix.

Fix: Wait for a green RTK badge, keep still and try again. A John Deere StarFire that shows DGPS on RTK: see DGPS instead of RTK.

You calibrated to the old ground, which is now at design

Fix:

1. Tap the BM badge to open Calibrate Elevation.
2. In the Loaded design row, tap Design grade (instead of Surveyed ground).
3. Stay on the run and lower the cutting edge onto the ground.
4. Tap Calibrate on that row. Keep still for 5 seconds.

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The file may be from another base setup

Check: The window says If your RTK base station location has changed since this design file was created, you should calibrate to ensure accurate grading. In Field Mode it may also say the file was tied to a different benchmark.

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Fix: Tap Calibrate if the base or the session changed since the file was made, then calibrate on your benchmark. Tap Skip only if you're sure today's calibration is right. Most workflows ask once per file each time the app is opened; Land Forming asks every time you apply a design.

The benchmark is wrong Most likely if it's feet

Check: Read the amount in the window. A few feet usually means a stale or wrong calibration.

Fix: Tap Cancel and recalibrate (steps).

You're at a deep cut or parked off the line

Fix: If the cut or fill is what you expect here, confirm and start.

The benchmark is off by a lot

Check: The BM badge is grey, or the line in Calibrate Elevation reads Restored from ….

Fix: Calibrate, ideally to the design's own benchmark (the Design BM row) or to a zero cut/fill spot on the loaded design. See Land Forming problems.

The antenna doesn't move with the cutting edge

Fix: Mount the antenna on the implement, on a part that moves up and down with the blade, on a mast tall enough to see the sky in every position. See Mount the GPS antenna. Ditch Assist Lite: the Reach goes on the blade, never the cab.