Working width and overlap
Short answer
Guidance lines are spaced at the working width you set, so that number decides whether passes meet, overlap or leave gaps. Set it to the width the implement actually covers, and use a slightly narrower figure if you want a deliberate overlap.
Updated · Oran Dynamics
Setting the width
On the Implements tab, add an implement and set its width on the ruler wheel, in metres, centimetres, feet or inches. Save one profile per machine (sprayer, spreader, mower) and pick the active one before you drive; each keeps its own coverage colour.
The app starts with a Default Work Width implement: 50 ft if your device region is the United States, 16 m everywhere else. Change it to match your kit.
What "working width" means for each job
| Job | Width to enter |
|---|---|
| Boom sprayer | Boom width (the width actually sprayed) |
| Fertiliser spreader | The bout width you spread at, not the machine width. Check the spread chart for your product |
| Slurry (dribble bar, trailing shoe) | Bar width |
| Slurry (splash plate) | The effective spread width you get, measured once |
| Mower, topper, roller | Cutting or rolling width, minus the small overlap you like to leave |
| Drill or seeder | Drill width (but see drilling on accuracy) |
Implement offset
If the implement sits off the tractor's centre line, set Implement Offset (left or right, with a distance). The phone's Mount Position in Settings can also be set left or right. Both offsets move where the swath and coverage are drawn on the map; the guidance lines and the distance-off-line readout are still measured from the phone's position. There is no fore/aft (hitch distance) offset in the current version.
Why overlap matters
Every overlapped strip is product applied twice and fuel burned twice. On a 24 m spreader, a 1 m overlap on every pass is about 4% of the field treated twice. On a 12 m sprayer, the same 1 m is about 8%.
Work out what that costs on your own farm with the overlap calculator: enter your acres, width, passes and input cost.
Questions
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The bout width you set the spreader up for (the distance between your passes), not the physical width of the machine.
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Yes. Save as many as you like; one is active at a time and each has its own coverage colour.
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You can set a left or right offset. It shifts where coverage is drawn; guidance lines and the distance readout are measured from the phone's position.
Try Tractor GPS on your iPhone
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Download the appRelated
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- Phone vs light bar vs autosteer vs RTK: tractor GPS options and costs What each kind of tractor GPS costs and how accurate it is, with sourced prices: phone apps (about $30–$100 a year), light bars ($1,500–$2,000), autosteer kits ($3,000–$12,000+) and RTK corrections.
- A-B line guidance on an iPhone What an A-B line is and how to set one in Tractor GPS – Field Guidance: tap A, drive, tap B, and the app draws parallel passes at your implement width. Set in two taps.
- Field guidelines and headlands For a saved field, Tractor GPS – Field Guidance can lay out the guidance lines for you: best fit, parallel to any boundary edge or a set angle, ranked by number of turns, with 0–10 headland lines.