Application map (VRA)

The application map (VRA = Variable Rate Application) divides the field into zones with a different application rate in each: fertiliser, herbicide, plant-protection product. DroneField builds one from your vegetation index in just a few clicks.

What it’s for

The core idea of precision agriculture: apply more where the plants need it, and less or none where they don’t. Typical applications:

Nitrogen fertilisation — more N to weaker stands
Herbicide — only where weeds are (Spot Spraying)
Seeding — for row-crops on heterogeneous fields
Soil-sample zoning — split the field into NDVI-similar zones to plan where to sample

Starting

Processing must have finished — at least the vegetation index needs to be available.
Draw (or import) a field boundary — this defines the application grid’s outer contour.
On the boundary toolbar click Application.

A new panel opens at the bottom of the map: Application map.

The application map panel

The panel contains:

Grid settings

Cell size — one cell’s size in metres. Recommended: 5 × 5 m — supported by most drones and ground machines. Smaller cells (e.g. 3 × 3 m) are more detailed but produce more cells; larger cells (e.g. 10 × 10 m) are coarser.
Rotation — rotate the grid relative to the field. If the field and rows are tilted 30° from the axes, enter that here.
Grid coverage — does it fully cover the field? (default 100%)

The Generating grid… progress bar shows when the panel is rezoning the field.

Zones

Since version 26.4, manual zones work with index bands instead of an equal-area split: you set a min–max index value per zone, and each grid cell lands in the zone whose band contains its average.

Each zone has:

Name — e.g. Weak stand (default: Zone 1, Zone 2 …)
NDVI / NDRE / GNDVI band — the min–max index range of the zone
Dose — l/ha (liquid) or kg/ha (solid, seeds); the unit selector shows one column at a time
Colour — for visualisation

How the bands behave:

A new plan starts with two zones: Zone 1 covers the whole positive band, Zone 2 is the “no treatment” zone (0 l/ha) — it always stays lowest, and it automatically receives the practically lifeless cells (bare soil, dried residue) as well.
Add zone inserts the new zone just above the lowest one by splitting the band above it — every value can be overwritten.
Overlapping bands turn red, a gap between bands turns orange. The magic-wand button next to the field snaps the neighbouring zone’s band to yours — the value you typed is never lost.
If you edit the bands of an AI-generated plan (AI vegetation analysis), you take over manual control of the zoning.

Statistics

At the bottom of the panel:

Zone 1: 3.2 ha — area of each zone
Total: 12.5 ha — total area of the field (with grid coverage)

These update live as you change the ranges.

Export

The panel’s Export menu:

XAG Spot Spraying

A special XAG drone mode: the field is split into zones, and the drone sprays only the marked spots. Optimised path, less chemical.

Before export a confirmation dialog shows the final zone picture — click Yes to finalise. For XAG Spot, Hardi and ABZ exports the confirmation panel now summarises per dose (colour + dose + area in hectares) instead of listing every polygon; the polygon count appears in a single summary row.

XAG VRA precision map

Conventional VRA: the drone sprays continuously, but the dose varies by zone.

DJI VRA precision map

For DJI Agras T20 / T30 / T40 / T25 / T50 drones. Same principle as XAG VRA. DroneField creates the full Exports/DJI/ sub-structure (KML/, ShapeFile/, Rx/) — copy this to the USB root as-is. Details: Field boundaries → Exports/ folder layout.

⚠ Don’t export a standalone boundary KML for the same field when you’re shipping a VRA map — the Rx map’s companion Shapefile already includes the boundary, and the DJI controller would list the field twice.

Video guide: create a precision map and import it into the DJI T30 remote controller:

Hardi VRA Shapefile

The standard for Hardi and other large tractor sprayers in ESRI Shapefile format (WGS84). Loadable in any European farm-controller software (CCI 1200, Trimble, Müller).

ABZ Innovation (L-S series)

Exports the field boundary and — for variable-rate jobs — the prescription map (Rx) in the format that ABZ Innovation L-S series spray drones read.

Choose ABZ Innovation (L-S series) in the export menu.
Set an Output name for the export.

What you get:

A <Name>_Boundary folder — the field outline, with obstacles included as cut-outs.
For variable-rate jobs an <Name>_Rx folder with the prescription zones: each area carries one rate, areas don’t overlap, and the rest of the field is included as a zero-rate area.

Two things worth knowing:

Simple whole-field jobs: if the field has no variable-rate zones, the export contains only the boundary — you then set the payload and application parameters on the drone / controller.
No-spray zones are included in the prescription as zero-rate areas automatically.

PNG / JPEG

A visual image of the application map — for presentations, client emails.

Step-by-step workflow

A typical N-fertilisation workflow:

Survey — drone flies, M3M, ~5 cm/px (or 3–5 cm/px for NDVI), in good weather (overcast around midday).
Import + Processing — multispectral enabled.
NDRE map — switch to NDRE in the vegetation index panel.
Range — e.g. Stress preset (0.30–0.65).
Field boundary — draw it or import the contour.
Application map — boundary toolbar’s Application button.
Zones:
- Zone 1: 0.30–0.45 → 180 kg/ha (low — weak)
- Zone 2: 0.45–0.55 → 120 kg/ha (medium — average)
- Zone 3: 0.55–0.65 → 80 kg/ha (low — already healthy)
Export — DJI VRA precision map onto the tractor’s USB stick.

Tips

Start with the recommended 5 × 5 m grid — supported by every drone and ground machine. Only go below 3 × 3 m if the machine’s documentation requires it.
Don’t add too many zones — 3–5 is typical. Too many overcomplicate the operator’s job.
Always check the confirmation image — tiny zones (1–2 cells) or isolated dots are often noise; consider excluding them.
Save as a template for the next season — the zoning parameters can be reused, only the data refreshes.

What NOT to do

Don’t rely solely on NDVI for N fertilisation of mature stands. NDRE is better.
Don’t use no-spray zones for dose marking — those are for drone-safety, not application.
Don’t forget to verify the export on the tractor / drone terminal — formats can be strict about encoding, and one wrong setting can ruin the run.

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