GPS app for spraying fields
Short answer
Yes, there is a GPS app for spraying fields: Tractor GPS – Field Guidance turns an iPhone into sprayer guidance with straight lines spaced at your boom width and a map that paints what you've sprayed. It suits grassland, pasture and any field without tramlines, at phone GPS accuracy (a metre or two on newer dual-frequency iPhones).
Updated · Oran Dynamics
Where it helps most
- Fields without tramlines: grassland, pasture, stubble and pre-emergence spraying, where there's nothing on the ground to follow.
- Spraying at dawn, dusk or at night, when the wind drops but you can't see your last pass.
- Weed spraying in rough pasture, where foam markers are hard to see or you don't have them.
- Coming back to a half-finished field: the coverage you sprayed yesterday is still on the map when you continue the job.
How to set it up
- Implement: add your sprayer on the Implements tab with the boom width as the working width.
- Plan the job (optional): in Work Log → Jobs, enter the product, application rate and tank size. The app works out how many fills you'll need and how long it will take, and shows a progress strip on the Drive screen as you go.
- Set your line: tap A and B along the first pass, or let the app lay out lines for a saved field, including headland passes. See A-B lines.
- Spray: tap START, follow the steering arrows and watch coverage fill in. PAUSE while you refill, RESUME when you're back.
What to expect from phone accuracy
The phone's GPS is good to a metre or two on newer dual-frequency iPhones, up to about 5 m on older ones (see accuracy for our measured figures). With a 12–24 m boom, that's enough to stop the obvious misses and double-sprayed strips that come from guessing the last pass, which is where the savings come from. It is not centimetre guidance, and the position can drift over a long job, so check against the previous pass and recentre the line if needed. For tighter work, an external receiver paired in iOS improves on the phone's own GPS; see accuracy.
In tramlined crops
If the crop already has tramlines, follow them. The app is still useful there for the coverage record and area sprayed, but the tramlines are your guidance.
Questions
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Tractor GPS – Field Guidance has a 7-day free trial with every feature, then costs US$89 a year in the US (prices vary by country). Some other apps have free tiers; see our comparison.
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Yes. Mount an iPhone in the cab, set the boom width, set an A-B line and follow the guidance. The map shows what you've sprayed as you go.
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A metre or two on a newer dual-frequency iPhone (typically 0.5–0.7 m side-to-side under open sky), up to about 5 m on older iPhones. That's enough to cut misses and overlaps with a wide boom on open ground, but not centimetre-level.
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Yes. Guidance and coverage only need GPS. Download offline images of your saved fields beforehand if you want the satellite background with no signal.
Try Tractor GPS on your iPhone
A–B guidance, live coverage mapping and field boundaries — using the phone you already own.
Download the appRelated
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- GPS for slurry spreading Use an iPhone to map slurry spreading: see exactly where the last load ran out, keep passes at bar width with a dribble bar or trailing shoe, and log area per job.
- GPS for mowing, topping and rolling Mowing, topping and rolling with iPhone GPS: a map of what you've covered when you can't see it on the ground, straight passes at your working width, and area logged per job.
- GPS for drilling and planting: an honest answer Phone GPS is accurate to a metre or two at best, which is not enough to match drill bouts or plant rows. Here's what Tractor GPS – Field Guidance can and can't do for drilling, and what to use instead.