Getting Started for Agronomists
Build your first variable-rate prescription map from satellite or drone imagery, end to end.
This guide takes you from a fresh portal sign-in to a downloadable, ready-to-fly VRA shapefile in under thirty minutes. If you've made prescription maps in other software, the workflow will feel familiar — the GTRV-specific pieces are flagged inline.
What you'll produce
By the end of this guide you'll have:
- A farm, a field, and a plot drawn inside the portal.
- A prescription map generated from either a recent satellite scene or processed drone imagery.
- A VRA shapefile that the pilot can load directly into the field controller.
What you need before starting
- An account with at least Member access. To create farms/fields/plots you need Member or higher. Owners and admins always have full access.
- The field boundary for at least one field. You can draw it directly on the map; you don't need to import a shapefile.
- A clear sense of the prescription preset you want — Recovery, Maintenance, or Neutral. See VRA Prescription if you're not sure.
The big picture
The Map Prescription workflow has three stages:
1. Select Farm & Field → 2. Define Plot → 3. Pick Imagery → Configure Zones → VRA → Estimate → DownloadYou move through the stages with the Continue button in the right-side panel; you can always step back with Back.
Step 1 — Farm & field
Open Map Prescription → New
Click Create New from the Map Prescription home page.
Pick a farm
Choose an existing farm from the Farm dropdown, or click Add New Farm, name it, and click Create.
Pick or draw a field
Choose an existing field from the Field dropdown, or click Draw new field. The map enters drawing mode — click to place vertices, click the start point to close the polygon.
Save the field
Name the field and click Create Field.
Step 2 — Define the plot
The plot is what the prescription actually covers. Two options:
- Use the existing field boundary — pick an existing plot from the Plot dropdown.
- Draw a new plot — click Create new plot, then Draw plot. The plot must lie entirely inside the field or the portal will refuse to save it.
Click Create Plot, fill in:
- Plot Name (required)
- Crop Type (required): Soybean, Corn, Wheat, Cotton, Sugar cane, Coffee, Rice, Beans, Other
- Season (required), e.g.,
2025-26
Click Create Plot to save.
Step 3 — Pick imagery
You can drive a prescription from either Satellite (Sentinel-2 by default) or Drone (OTM) orthomosaics.
Satellite (fastest)
- Click Search Satellite Image.
- The portal looks for the most recent scene with acceptable cloud cover.
- Toggle the view between True Color and NDVI (Health) to confirm the scene is usable.
- Click Save & Proceed.
Drone (highest resolution)
- Click Upload Drone Images.
- In the drawer, pick the farm + field, drag your raw drone images in (or click to browse).
- Click Start Processing. The job is queued — watch progress on the Photogrammetry tab.
- Once status reads Completed, return to the wizard, pick the processed dataset from Processed Images, then click Save & Proceed.
See Satellite vs. Drone Imagery for when to pick which.
Step 4 — Configure zones
You're now in the Zone Editor drawer. Choose:
- How many management zones you want — Low, Medium, High.
- Method to compute the zones:
- K-Means — equal frequency clustering. Good default for most fields.
- Jenks Natural Breaks — minimizes within-zone variance. Best when NDVI distribution is bimodal.
- Quantile — equal-sized groups by area.
- Equal Interval — equal NDVI range per zone.
- Block size (meters) — 3 to 50. Smaller = finer detail, larger product file.
- Prescription preset:
- Recovery — apply more product where NDVI is low.
- Maintenance — apply more product where NDVI is high.
- Neutral — uniform rates across zones.
Click Generate Zones Automatically.
See Management Zones for a deeper look at each method.
Step 5 — Tune the VRA prescription
On the VRA Prescription step you can:
- Manually adjust application rate by zone.
- Set classification thresholds — the NDVI value below which a block is "Low Vigor" and above which it's "High Vigor".
- Redistribute blocks between zones by clicking blocks on the map.
- Merge zones that turn out too similar.
- Draw exclusion zones (no-application areas — useful for waterways, headlands, sensitive corners).
Click Generate VRA Prescription when you're satisfied.
Step 6 — Product estimate & download
The final step shows:
- Total area of the prescription (in acres or hectares, depending on your unit setting).
- Required product (total volume or mass).
- Estimated flights (rough estimate of drone-hours needed).
- Avg. rate across the prescription.
Click Download Shapefile (.zip) to grab the package. It contains the polygons and the per-zone application rate that the controller reads to drive variable-rate spraying or seeding.
Where to go from here
- Prescription Maps reference — every option in the wizard explained.
- VRA and zones — designing better prescriptions.
- Satellite vs. Drone Imagery — choosing the right input.
- Exporting shapefiles — file format, field mapping, controller compatibility.
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Last updated Oct 20, 2018