The story behind TerraZoner
Fifteen-plus years looking for this tool. So I built it.
I'm Simon Knutson. I've spent over fifteen years working in the industry alongside growers, agronomists and drainage crews, and I never found a zone map that told me why the lines were where they were. TerraZoner is that tool, built for the operators who have to stand behind the map.
- 15+ years in the industry
- Built for Canada & the USA
- Browser based
Performance Zones grades every field on the same fixed scale, so one that performs alike can say so, before you draw a line.
- Founder-led, independently developed by GIS4AG
- Satellite imagery included, nothing to set up
- Runs in the browser, nothing to install
The tool I kept looking for never showed up. So I built it.
For over fifteen years I've worked alongside growers, agronomists and drainage crews on real fields. In that time, every zone map I was ever handed was a picture with no reasoning behind it — colors on a boundary, no explanation for why a corner got its own zone, and no way to tell if the field had enough difference across it to be worth splitting at all. What I wanted was a map graded the same way every time, one that would land in a single band and say so when a field didn't need zones in the first place. TerraZoner is that tool.
Simon Knutson created TerraZoner and leads the GIS4AG team building it. Under GIS4AG, Simon also created Geo-Surface Pro, his drainage-design tool. He is a co-owner and the creator/developer of Ditch Assist, a separate venture. That field work — years spent standing next to the people who use what gets built — is where the "explain it to the grower" standard comes from.
Zone maps with no reasoning behind them
- A map handed over with no way to check it
- A push to zone every field, whether the differences said so or not
- Scores and acronyms in place of a plain answer
- No way to tell a grower why that corner got its own zone
A map you can explain, built on evidence
- Composite Zones and Performance Zones built from seasons of imagery you can point to
- Graded on the same fixed scale every time, so the map itself can say a field doesn't need splitting
- Plain language and a fair number of zones for the fields you manage — no scores, no jargon
- Every zone traces back to imagery, terrain, or both
Three answers, one tool — each built as a core part of the map, not an extra bolted on later.
The years
Composite Zones, and one-click Performance Zones, built from seasons of satellite imagery — graded on the same fixed scale every time, so a field that performs alike can say so.
The ground
Terrain refinement and Landscape Response from public elevation — US 3DEP and Canada HRDEM built in, RTK-quality points anywhere else.
This week
The In-Season portal: scene search, crop-vigor views, and flood, hail and drought damage estimates with a report.
That's the tool, and why it works the way it does. See plans and pricing See the features
Built by someone who works both sides of the field
TerraZoner is one of three GIS4AG-family tools Simon Knutson has built or co-built. The connection between them is practical experience and compatible files, not a requirement to own another product. Each one solves a different job on a real field.
TerraZoner
Satellite-based management zones for row-crop fields — an independent GIS4AG product, founded and owned by Simon Knutson.
See what it doesGeo-Surface Pro
Drainage design that runs in the browser — also built by Simon Knutson under GIS4AG.
Visit geo-surface.comDitch Assist
On-machine grade control for putting drainage designs in the ground — a Northern Plains Drainage Systems product. Simon Knutson is its co-owner and creator/developer.
Visit ditchassist.comYou don't need Geo-Surface Pro or Ditch Assist to get everything TerraZoner offers, and you don't need TerraZoner to run either of them. Nothing here is bundled or gated behind another product.
Tools you can put your name on
A zone map carries a name and a reputation. TerraZoner carries mine. These are the principles that keep it honest in the field — not just convincing in a demo.
We tell you when a field isn't worth zoning
Performance Zones grades every field on the same fixed scale. One odd season gets flagged, not quietly averaged in, and the map is allowed to say no.
If the field doesn't support zoning, we say so. No zone tool should talk you into a map the field can't back up.
Support from people who run the work
Questions stay close to Simon and the small GIS4AG team that builds, tests and supports TerraZoner — not a script-reading support desk.
The people answering are the people who built it.
Built for North American fields
Sentinel-2 imagery at 10 m, seasons back to 2015, anywhere in the world, included with membership.
Elevation loads on its own across US 3DEP and Canada HRDEM; upload RTK-quality points anywhere else.
Who's behind it
Who makes TerraZoner?
What is GIS4AG?
How is TerraZoner connected to Geo-Surface Pro and Ditch Assist?
Draw a boundary and read the field in an afternoon
Open TerraZoner, draw a boundary, and see the years, the ground, and this week — all in your browser.
Need to size up storm or drought damage this week? See the In-Season portal.